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.
Solo- you just keep transfusioning the other champion till you think you will kill them with ease. I prefer the ignite ult transfusion method. This can kill anyone with below half hp.
Mid game- keep leveling get to 18 as fast as you can. I prefer to gank people every 5 minutes. WIth this build you should be a super tank. If done right you can tower dive at lvl 6 with ease.
End game- Run in to group fights after any tank and just start Aoeing everyone you can while transfusioning the enemy champion with the lowest hp.