How does stratagy and current meta come to be?

Now I'm no superstar league player and most likely never will be (bronze1 scrub) but I do really enjoy the game. A lot of my friends now play league and it's become kind of our past time. I do have a few questions for players that are a bit more experienced then myself and they all are based around the "meta" or strategy of the game.

First off, like I said I'm no superstar but I would like to get better at the game. I've been watching streams and youtube vids on player mechanics, counters etc. But what I am having trouble finding info on are things like, current "meta", team comp strats, decision making strats (when to push for what). Things like how to push advantages, how to split the map an so on. I know at my ELO in soloq these things basically dont exist but I still would like to better myself.

So to anyone out there who is knowledgeable about these things, how do I go about learning them? Where would be a good place to look for material or info? Is it worth trying to join a team to learn more about the game or focus more on soloq.

Any info helps! Look forward to some advice :D