New player help; tips needed

So I've been playing league for about 2-3 months now, and i'm still pretty much in the dark on how properly learn this game. what i'm looking for is actual advice to increase my playing ability and overall have fun, cause consistently losing match after match after match with negative k-d-a stats if getting frustrating. also, when i queue my teammates don't do anything but harass and troll the living piss out of the chat being extremely toxic towards myself even when legitimately am trying to ask for advice.

so gimme all the constructive advice you guys can throw at me. i wanna get good at this game so i can play with my friends and not hold them back every game.