@solarsystem87 there must be thousands of people stuck in the same position as you saying similar things... "I'm dreaming of...I don't have much time... I don't know how best to do it." You ask about "how to write your own first book" - I assume, as with most similar cases I've come across, it's with a view to publishing. You ask "What is the best way... to have success with your endeavour?" Maybe this isn't what you are hoping to read but here's how I look at things:
What is success? What is it to you exactly? What do you want? A cardboard box full of expensive books you paid for that you can only give away to friends and family? One copy to hand down to your kids? The truth is it's relatively easy to write something, anything and to self publish (as an ebook, for example) - is that really what will satisfy you?
You seem to be saying you are at point X and you want to be at point Y and you're asking for directions from passers by as to how best to get there.
I think there's another way you could, perhaps should, be looking at this; it will sound like a tired cliche but - what about the journey? (from X to Y). and whether you enjoy it.
On various forums for creative types it's common to see people posting about their distress at writer's block (I do not believe in it FWIW) or frustration with some aspect of the creative process - in a nutshell - I think - "if you don't enjoy it, don't do it" or to say it the way I normally do - "you have to learn to love the process (all of it)" so this means focusing, not on the destination (point Y) -
and thinking that reaching that point is the only part of the process that will bring you any joy, but on the journey - what you do every day - ATM I think you should only be looking at trying to cultivate an attitude that will help you enjoy the writing process and to see that you should be enjoying the daily task of writing a few satisfying lines or deciding on a direction, a perspective, a scene, a point, a some part of the structure, etc. I look at the creative process in a similar way to the way I look at crosswords - I like crosswords; do you? I see them as the puzzle they obviously are - I don't mind if I can't finish it in one sitting - it's very common to come back to a half finished crossword and suddenly see answers or different ways of looking at the clues - sometime it takes time for ideas to come to fruition - to see the right answer or approach - or sometimes - I have to look something up - an historical fact. So - I don't see writing creatively as that different to doing crossword puzzles - and I enjoy the process of filling crosswords in in the same way that I enjoy writing. I taught A-level maths for 12 years - I get the same enjoyment from completing new problems - it's not just finding the final solution - it's the process of solving them - and there are always many ways - some ways have more aesthetic appeal appeal than others. So my first suggestion is that you learn to love what you do, focus on that.
Perhaps a second point is to think more about becoming a great writer or maybe a better writer or an improving writer - first focus on becoming a better writer. You might have heard Paul McCartney say that the Beatles (really just him and John) wrote more than a 100 songs before they wrote a good one; it's a process to become a good writer, a journey for you - you won't go from enthusiastic amateur to published author in one book (unlikely I think!)
There's no simple way to do this - if I was you I would write, show and share your work (or fragments of it) and look for feedback - it's up to you what you do with that feedback - you can't always pander to everyone else's opinions - it's good to break your own new ground and to go in search of your own voice. I am lucky that I have a writing partner - a valued friend of over 15 years now that I share my writing with - we struck up a conversation on a poetry forum and continue to message each other several times a week (she's in another European country) - we met only once about 7 years ago but we will meet again one day. It's useful having someone whose writing acumen and opinions you value and respect. Read - they always say and I agree - but not just for pleasure - you have to be analytical - mercenary even - and work out what makes, what you are reading good (appealing to you) or conversely - bad. For instance, I was reading Bob Mortimer's loosely (debatably!) factual biography "And Away" - it's a laugh out loud read but I don't let myself get distracted by that - off the top of my head what I liked about it was the structure (for one thing) - short chapters that alternated between chapters recounting amusing incidents from the past and far more sobering chapters that were full of disarming honesty concerning his present day serious health worries; the distant past came closer to the present in each of those chapters as did the chapters concerning his health problems. The short chapters meant there was never too much, never too long a chapter, on either the comedy or the pathos. No doubt the structure is far from unique but it's what I noted and it was part of the reason, IMHO, why the book worked so well (for me). I was reading a Mary Ruefle poetry book for a few days while away on a short break last week - what I liked about a few of her poems was the way she flips between lines that were very much rooted in everyday reality and lines that were born out of imagination and used a lot of figurative language - it gave me an idea for how to tackle a poem I have wanted to write for a decade but I didn't know what to do with my idea - something traumatic that I recall from being in hospital when I was 7. Reading Ruefle's poem Provenance was something that made me want to write. So - I don't just read for pleasure - I read to learn about writing. Reading is always recommended but I'd say it can also become a distraction, a displacement activity instead of doing your own writing. I have something I'm working on about my daughter's illness - I read easily a dozen books written by other people on the same subject - it helps me know the terrain, know what has already been written - it's helpful to have some idea about where I might be able to do something different to what is already available. OTOH - reading can also be demotivating - when you read something incomparably wonderful.
Point 3 - something I've noted from many areas of my working life - it's always a mistake to look for a "magic bullet" - a single simple solution that will solve a complex problem; don't ever start looking for one - you'll be wasting your time. You're asking about how to write a book - I don't think there will be a single, simple "answer" that is going to help you TBH. There is no one single best way for you to get from X to Y - you have to make up your own way of getting there, and find your own way to enjoy the journey; what works for you is the right way (for you) - so you could try out suggestions and see if they work for you - what works for me may well not work for you. I wrote a lot of songs in the last 15 years - there is no single method of working that I stick to - the songs all have their own unique way of coming into being - some come quickly - others takes weeks/months/years and require a lot of thought, rewriting, editing, alternative version, restructuring, etc. i.e. crafting. There are many things I believe in or think that shape the way I work - "You can't wait for inspiration - you have to go after it with a club (like a hunter)" - Jack London. I believe in the power of the "flow state" - you'll probably know this when you experience it even if you aren't familiar with the term - in a flow state ideas come together almost effortlessly, new ideas come thick and fast, you find it easy to edit and make decision on the hoof - it's sometimes a mystery how you get yourself into the flow state but most often, for me, it's by putting a pen on a page and deciding to write something, anything - I don't think about inspiration - you just write the simplest plainest ideas down about something you want to write about - if I stick at it - keep going - I can sometimes/often/ occasionally get into that flow state I value (and enjoy) for writing. Sometimes I find myself in a flow state and I'm not sure what got me there - listening to the radio, doing the washing up, walking the dog - anyway - I make a point of riding the wave when it comes - I was composing haiku's in my head about my days while on a trip away in my camper van the other week because I was in bed earlier than normal and wasn't tired so once I'd worked one out in my head I put the light on a wrote it down - I do this regularly when I'm away - thinking about what I've seen that day - so it's a case of striking while the iron is hot. Another thing is something I took from reading Sylvia Plath's diaries - a telegram she wrote after fracturing her fibula while skiing is a great example - take a look and ask yourself - why would anyone write that way? My reading of this is that she is constantly at play in her writing, and took every opportunity, however mundane, to try and spontaneously bring new ideas to life, to find new ways of using words together - you can do it writing an email, a text message, replying to a post on a forum - SP did that in her diary entries - I think it helps to always try to be "a writer".
I'm hopefully pushing you to think about just writing, becoming a better writer and realising that writing a book is something you may find yourself doing one day but to begin with I'd just focus on your writing day to day, enjoying it and see where it takes you. I think that if you're struggling with the idea of how to write a book - maybe you are not ready. Maybe one day you will be. I balance that by also saying that it's a mistake though - to think that you can or should only write - when you feel like it or have an idea - sometimes you just have to work at it and by that I mean start writing a few lines - I'm doing this tonight following on from reading that Mary Ruefle poem. HTH.