Welcome along, they’re a friendly bunch, even if you do drive a BMW!
I know first time polishing can be daunting but it’s worth putting the time and effort in to get a good understanding of what is going on, although at our age (not very far behind you) the prospect of doing a full correction and ceramic coat just makes me ache. My car was written off last year (by a BMW driver!) and didn’t find a replacement until November so it’s just had maintenance washes so far, so I’ve got that to look forward to. Gave it a service today and the hardest part was getting back up after crawling around underneath the damn thing.
Good choice of products, autowheel is a personal favourite but unless your wheels haven’t been cleaned in six months you can get away with watering it down to at least 50/50 and it’ll still do the job but last twice as long. The warnings about direct sunlight and not letting things dry are good advice but basically the same thing, any chemical you leave to dry will leave a residue, some will even stain or discolour but most will just be a pain to remove, so always rinse well. Direct sun makes metal and glass very hot, so things dry faster, and you get the idea.