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.
I have seen many Ryze builds with just mana and almost no AP, my opinion is that it sucks. This builder has a middle ground that makes it unique :D It has both a lot of mana and a lot of AP. You're going to laugh at it :p
Skill Squuence is easy, first E -> W -> Q. after that the enemy is pretty low on HP, but ofc when u got ur utli R use that before everything :)
When u use W first u reduce ur enemys magic resistance followed by ur root who also does damage and finnish spamming Q.