Noob

So guys I won't say I haven't played CS:GO at all but I have played only few times on my friend's account and finally bought one for myself during the steam sale. Now I don't know many things about the game and its concept. I mean I have played CS 1.6 and CZ but it was kind of different and I have only played in game zones who used those Russian pirated copies. So if anyone would be kind enough to teach me basics I'll be more than grateful
Btw by concepts I don't mean how to play but the whole system. Anyway thank you in advance