The wiki is huge and I feel like reading it would be a waste of time. Experience is best gathered in the fieldI could try help you out with any questions you have or teaching you the basics of the game if we're on at the same time, other than that your best bet if you can't get somebody to teach you are wikis, most servers should have a wiki explaining the basics of the game and going into detail regarding aspects of it such as departments, crafting and combat.
i learnt how ss13 works just by playing it with a friend @moonman
over time, you'll learn how it works. stick to some low rp servers like goonstation or presumably hippie before jumping into some higher rp servers where the edgy admins ban you for not knowing most basic stuff.
just a tip for you brother, don't join citadelstation, you'll regret it for the rest of your life. just don't, don't, don't
in case you really do want to know what's there, shoot me a forum pm but expect nasty stuff