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.
Start with your Amplifying tome and hang out close to the golem, but wait until you see all the enemy champions in their lanes before starting it. You don't need smite to take him down at level 1. Focus on the golem and not the lizards. You will have about 1/5 life left so don't mess it up. Get lizard asap as it will help you jungle/gank better.
When you get lvl 6, you can start ganking lanes from the bushes. Always dark wind + terrify while chasing them down with ghost/flash. You should always get at least one kill on your first gank with both summoner spells up.
Mejai's will be your major source of AP, as you don't really need too much since your spells do so much damage already. Focus on survivability so you can dish out all the damage and not lose your stacks.