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.
Engage with a Q follow up with an E or R depends on situation and champion, and finish with the remaining E or R.
Use your flash as an engage in the middle of the enemy team, follow immediatelly up with your ult for the 0.5 second silence. Let your teammates know when you're going to do this so they can follow up when all the enemies are silenced.