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.
Just follow the guide and you should be good. And try to take map control by warding whenever you have 75-125 extra gold this also helps you with your teleporting options so try and put them behind the enemies and hidden so you can get a sneack attack with your other teammates that got teleport spell.
Harass them with bombs as much as you can then use your clarity when needed.
after that when your low hp go back and heal then teleport to your setup ward [hopefully you chosen a good spot somewhere hidden and behind the enemy lines] .