new to this great game

Unwritten rules, like who goes where, can probably be considered more "META" than rules. META stands for Most Effective Tactic Available. Simply put, League's top lane has mostly tanks/fighters, with some marksmen like Quinn opting to go top lane instead of bot lane, mages/assassins mid, near anyone can jungle, but junglers are mostly tanks, assassins, or fighters, with tanks being the best junglers right now because Courage of the Colossus is busted, marksmen in ADC, supports, mages, and tanks in support, with those 2 going bot lane. The META is mostly defined by what's the strongest at the time, with the professional players often playing the best and determining the META.

The YouTuber Phylol is doing tier lists for all champions. In regular play, he's in high diamond, however because Flex Queue is so weird, he got placed in that lower than he's ever been, high silver. Here's a link to his channel: https://www.youtube.com/user/ThePhylol and his second channel, Phy Games, is where he plays ranked for us: https://www.youtube.com/channel/UC6FQVPzwKbcXr4wq9o0QKpA/featured