In my case, it was a combination of YouTube and what I call my 'acquired grandmother', i.e. a lovely older lady who could sort out my patterns when it all went a bit wrong!
Start with the basics, so casting on, and doing knit and purl. Try out newer patterns marked 'for beginners'. Very old patterns just assume that everyone can knit, and that's where YouTube can come in handy, because they do not explain how to do new stitches. If you end up on Ravelry, just make sure that you haven't got anything else planned that day, as it is a complete rabbit hole, and you might only surface when you realise that it's gone dark outside!
Find the needles that work for you. Some people like straight needles, bamboo, or circular. Don't buy expensive merino wool to start with. Cheap acrylic will be fine while you're learning. Wool Warehouse has a good selection of yarns, if your local wool shop is expensive/unfriendly/has opening hours that don't work for you.
Also, if you are not in the habit of sewing up patterns once they're done, try to work out how to do everything without seams! That way, you won't have that cardigan that you knitted for your DC still sat on the side when they're 18.
It is addictive. Accept that all storage space will be home to yarn, needles, safety pins, etc. Then you'll probably end up taking up crochet, spinning, sewing and- for the truly ambitious- lace-making or mastering knitting machines or something. And if you have pets, your ball of wool WILL end up wrapped around your dining table and chairs at some point in your life.
Other than that, OP, have fun! Try everything, and don't be afraid to make mistakes, or to ask for help if you need it. Good luck!