Phase 1: Prey comes after Wild Charge
Phase 2 (Adds) : Double Prey pretty much immediately after adds spawn (Have your tanks pop CDs, so you can spare 1 GCD to adlo/stoneskin victims)
Phase 3 : After Heat Lightning strikes (Not HL + Wild Charge combo, just HL).
Phase 4 (Adds): Similar to Phase 2, but due to the nature of additional adds, there will be a consecutive double Prey coming up as well (not simultaneous, more like 2nd prey icon appearing 2 seconds after 1st prey icon appears)
Phase 5 : Always after HL + Tether combo, Prey will combo with Critical Rip as well, better assign 1 healer to handle Prey and another to handle Rip.

Preys are extremely scripted, just get ready when you know 1 is about to come up.