So guys it's really simple the way u play this.
The major issues with this build is that u wont scale as easly as u do when u build liandry's, but, as soon as u start getting your first kills you will notice that the damage will ramp up. No one expects that much damage so you will almost feel like an assassin.

But now, how do you play it. Versus assassins/mages, you just want to poke them out the wave and farm as much as you can. Don't try to kill them, focus on the minions.
Versus bruisers you can and should be more agressive everytime they run to you, it's very easy to get a kill versus them.
Every now and then try to leave your lane and help your teammates, every assist counts to your rune and later on it will help a lot. Once you get your mythic the game begins. In perfect conditions it would be good to have at least one assist by now, the reduced cooldown on your item makes that every E is garanteed to proc. But now here's the real secret of this build. If your Q proc your mythic they will do an insane amout of damage. Later on the game you will notice that no one will be expecting that and that's the main reason i think this build is wayyy better than the liandry's one. You can almost play as an ad mf but with wayyy more range because of your E.

Don't u ever think of going close quarters 1v1s unless you are incredibly fed. You are a squishy champion and you probably will die. This build ramps up better in aram but works really good in normals too. Maybe give it a try in normals and don't run into ranked expecting to win 1v9, it's a off-meta fun build, if you are searching for a mega op build to win games better go adc with eclips, at least until her kit gets reworked. You can either go mid top or supp. I don't recomend it adc because you will scale really slowly in the begining versus the enemy's adc. If you go supp better build Rylai's Crystal Scepter second item since it's a nice slow.

The main combo is literally E + R. Pretty solid, can kill almost any champ if they aren't fed. Usually good if you are in a place with no vision. When using R make sure that the enemy is maybe in the middle of your range since there will be the spot where you probably will deal more damage and also be enough away from him to run if needed.
That's all hope you have fun playing this and be welcome to comment!