Youre asking such a broad and well documented question that it'd behoove you to just google it rather than expecting people to break it down
#Where to start?
cinder ember
Youd find extensive walkthroughs at your leisure rather than waiting 7+ hrs for someone like me to say something. My recommendation is to go to google and type that in + "reddit" and you should be taken to 100s of r/mcat pages which will give you the same basic run through of what to do
It should be some mix of find some content like kaplan which you can DL for free, anki which is free, get a qbank like uworld -which you should invest in if youre smart- and do aamc which will cost you money
If youre actually poor and not just cheap, there is fee assistance for free aamc material and reduced mcat cost