Elwigo help

[kyulol]

Hello,
I discover this addon https://www.curseforge.com/wow/addons/elwigo and it change my life.
It work with bigwigs but with some majors buff.
As a priest i can for exemple create my own bar so i can literally create a fake spell to a raidboss wich will tell me when i have to use my ramp based on a timer. Ihave to choose a name and a timer (0.16sec, 1min.45sec...)
Where i'm struggling is for boss with phase like Shriekwings for exemple.
I don't understand how to handle boss with phases.
If anyone have a solution or documentation ? i'm in =)
Sincerely For the Horde,
Kyulol