arc lightning build question

I'm using this build https://www.youtube.com/watch?v=fB_AytI8rvE&t=625s&ab_channel=Phoenix

just about got everything to the gear plus jewels. But the issue is i cant sustain Righteous fire. When should i proc it? keep in mind i"m very new to this game this is my first league. I'm wondering if this build is outdated. I do tons of damage that's not an issue but i want to use this build to its full potential.

im also running this build this season and i'm also new i canty figure it out either

Alot has changed in the year since that video was posted. I would not follow that build due to its reliance on aged mechanics.
Your build could probably be salvaged with some help from others, if you make your profile public so someone could take a look.