Hello! I am Chaos, I've been playing Garen since I started the Leauge Of Legends so I would love to talk about him and hopefully help you learn about the champion and any feedback (positive or negative) would be great help me get better at these.
I will just briefly talk about Garen's Roles ,
Roles : Before talking about his main role let's talk about the more (Unmeta picks) the option of mid isn't the worst idea ever because he does have one of the few silences still in the game and having a ton of early game damage means you can have a great start and you also counter some of the good mid picks at this current time (Zed and Akali) so still an option.
Personally that's as far from top as I would go from as Garen because Support he doesn't bring much for laning phase and "ADC" he would just be poked beyond hell.
For jungle he can't really do much when ganking forcing you to use teammates cc (And in solo que with that one guy who is like "Top Or Feed Fiora with TP + Ignite" that might not be the best idea) but can still be done but really the payoff isn't that great.
Top Lane: Top lane the land of promise and it can be all yours Simb- Sorry got sidetracked, the top lane meta is shifting quite a bit at this current time so where Garen stands is questionable (Some meta favour top ap and now solo que is favouring a bruiser top) but Garen's early game power is something very few laners can stop, is silence is great for lane and teamfights and his tankiness is amazing also with his passive at level 16 you can stand back and get back all your lost health in a few seconds. Build him Tank, AD, AP (Wouldn't Recommend now that DFG is gone or in general) he will always be a strong choice.
Pros / Cons
Strong Early Game Making it easy to win lane against most match-ups.
Passive at higher levels has a short cooldown and high health % rate.
Has one of the few silences in this game.
Ultimate is an execute and magic damage so it means armour will be worthless against your ult.
Q allows for escape or chase with the movement speed buff.
His damage output mainly falls off by late game.
Poke can stop your passive denying it's full effect in lane.
Can be kited pretty easy.
Besides the silence he has no real cc.
First off we gotta talk about dem skins, Now Garen is one of the few champions that you can get a free skin (DreadKnight) for so you don't need to rake out the wallet.
I always Dread talking about Garen's Skins....... Sorry.
Now most the older skins are outshine by the newer ones but Commando (Besides being manly than Chuck Norris) blocks 1 Damage off all of Leona's spells (I know game changing...)
The 520 Skins are a nice change (I own all skins from mysteries gifts) but compared to newer skins they don't stand up so pretty much 5.5/10 (Besides Commando 11/10).
Dreadknight and Rugged are both 975rp and they both look really cool but in my opinion Rugged is cooler, in game and the art so Dreadknight (7/10) Rugged (8/10)
Steel Legion, 1350rp Skin and DAMNNNNNNN it's so smexy, it makes your ult from a yellow sword of justice into A BLUE SWORD OF JUSTICE (That sounded cooler on paper) but in all fairness it is a sweet skin and looks amazing in game and makes getting a kill with your ult all that more satisfying (10/10)
But remember Spin To Win and Skins Get Wins so by playing Garen with a skin you basically Garenantee a win.... I am really sorry