League of Legends Roles!
This is going to be a quick summary of all the roles played in League of Legends main map, Summoner's Rift. There are always meta shifts and changes that can mix shit up, but this is the standard meta, that we have has most of the time.
Top Lane
Top laners are usually players who like to play alone and then carry, because if you aren't high Elo you really can't help other lanes before it's too late, so you have to carry your whole team. These are the classes played on top lane.
Bruiser - this is a class type that's meant to deal damage, but also is pretty tanky, usually you buy 3 damage items and then go tanky, but you are the easiest one to kill and also you deal the most amount of damage. Some examples are Irelia, Jax and Riven.
Juggernaut - juggernauts usually deal medium damage and are more tanky than bruisers, but juggernauts can easily deal more damage than bruisers. Juggernauts are usually built that way that they have to have some setup before they can deal the most damage possible. One example is Darius, his passive gives him more damage if he fights longer. Juggernaut examples are Darius, Yorick and Nasus.
Tanks - This class of champions are built to soak up damage and not to deal much in return. They are really good in the mid and late game, but are pretty much useless in the early game. Some examples of tanks are Maokai, Poppy and Shen. 
Mid Lane
Mid laners are usuall good for players who like to dominate their lane and occasionally help other lanes. Mid laners deal the most burst damage compared to other lanes. Here are the classes played on mid.
Mage - Mages are the classes that use mostly ability power and they deal a lot of damage. They are looking to burst out squishy targets from the back lane. Most of them can roam easily and help other lanes. Some examples of mages are Ahri, Syndra and Ziggs.
Assassins - assassins are pretty much self explanatory, they deal a lot of damage in the blink of an eye and they have a lot of movement to get up to squishy characters ass. Some exmples are Zed, Ekko and Fizz. 
Bot Lane
Okay, this is going to be fun to explain. Bot lane is played with 2 players, marksman (ADC) and a support. This is because marksmen are really low hp and can easily be killed. Here are the roles explained.
Marksmen - Marksmen are the most squishy targets and that's why they are played on bot with support. Marksmen are long ranged damage dealing champions who build only damage, attack speed and critical strike chance. They don't go tank at all so they can to deal as much damage as possible. ADC means Attack Damage Carry. Some examples are Caitlyn, Vayne and Draven.
Heal/shield support - These are the kind of supports who heal and shield you. They won't engage because they don't have the utility tp do that. They are like walking ambulances. Some examples are Soraka, Sona and Janna.
Tank Support - This support class is meant to help and defend you, they can engage and use crowd control (CC) to lock your enemies down and basicly hold your hand when you get caught. Some examples are Alistar, Leona and Thresh.
Damage support - This might feel weird to some people, but let me explain. These kind of supports are meant to go full damage, and deal as much damage as possible so ADC can just easily get the kill. They don't help you in the sense and heal/shield and tank supports help you, but they can be much more useful to dominate your lane. They are usually mage champions who are just better in the bot lane. Some examples are Brand, Zyra and Lux. 
Jungle
This is the most confusing role in LoL, because technicly everyone can be a jungler, but there are a lot of champion that are just better at it than others. Junglers biggest role is to get other lanes ahead. Usually that means ganking your lanes and helping them get a kill by surpising an enemy, but also you can just keep your opponents jungler down and that's still helping. Jungling is for people who don't like to lane against others and to play PvE in a PvP game. There are 2 main types of junglers and I'm going to try to explain them the simplest way possible.
Ganking junglers - These trypes of junglers are the ones that get to level 2 or 3 by jungling and then start to gank like monsters. They are really annoying to play against because they are built to be good at the early game and when they surprise at the right time you are going to die. They are usually assassins or bruisers, but even some mages are ganking monsters. Some examples are Vi, Kha'Zix and Xin Zhao.
Power farmers - They are the types of people who like to afk farm, they gank sometimes but mostly they want to farm up, just to get to that point when they deal crazy amount of damage or when they are unkillable tanks. Some examples are Master Yi, Sejuani and Udyr. 
Thanks you for taking the time out of your day to read my post. Have a nice day :) !