Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
this is not a guide. look at it as the basic information you need to play this champion. items, item orders, summoner spells, runes, etc. can vary in different games. it is possible to reach master/challenger playing this, but in order to do that, you need to learn how to play this champion & how to carry with him.
i recommend spectating high elo players (pref korean) using op.gg (or watching replays of them), as well as playing this champion a lot by yourself. don't expect anything from doing nothing and simply copying.