The 'amazing, easy to navigate' platform, or one that is at least perfectly fine and almost certainly charges less than your bank is Vanguard.
What you want is a stocks and shares ISA with them. However, you probably want to know more about why you want that and which fund you should pick.
You mention a book and a podcast. If it's not Meaningful Money, you should also give that a go.
www.amazon.co.uk/Meaningful-Money-Handbook-Everything-everything/dp/0857196510
meaningfulmoney.tv/mmpodcast/
There's loads of back episodes. A lot cover investing and some cover other things like mortgages and pensions. A couple I've recently listened to that were useful as a novice investor in helping find out what I don't know and whether or not I should worry about it are:
meaningfulmoney.tv/2017/01/18/how-to-choose-a-multi-asset-fund/ good for narrowing down an overwhelming number of funds to go in your S&S ISA.
meaningfulmoney.tv/2022/05/11/drawdown-or-annuity/ - I think it was this one - he talked about a technique where you buy a few different funds (once you start looking in Vanguard you'll see what I mean) then you just pay into them/leave them to do their thing and when it comes to the time to take money out, you can take money out from the one that's performed the best, and not touch any where the value has lost, because that's how you lose money by investing.
I found that this helped me worry less about getting it wrong as in choosing the wrong fund. Because in Vanguard, you can just pick a fund and invest some money, so I've just been picking a few of the most popular ones and putting money in each - I'm investing to provide an income in around 10 years time when I hope to retire or go very part time and will need to top up a small historical pension that will start paying at 60, but won't be enough to live on until I get the rest of my pension and state pension at 67/8. So then I'll be able to take money from the ones that have done well and leave alone any that aren't
I've listened to a good chunk of this podcast over the last 2/3 years and have learned so much. I've been wanting to invest for around a decade now, but was put off because I didn't know what I was doing and didn't want to get it wrong.
However, I've now learned that, as I've said above, it really is as simple as putting a bit of money in a S&S ISA and leaving it alone. Investing is what you should do with money you can afford to not have to use for at least five years.
So you have to make sure you've paid off any bad (ie expensive) debt first and have a decent emergency fund (size of which dependent on how secure your income is)
Also have a look at ukpersonal.finance/flowchart/ to see if you're at the stage where investing is right for you.
Good luck