Before Pull
Pop a nature prot pot.
Assign priest to renew, shield, t2 proc on tank (to be applied before each web spray)
The fight
There are two important abilities: Web Spray and Cocoon.
The Cocoon will trap 3 people until someone kills said cocoon. During this period, the player will take damage and require extra healing. You can add the debuff “Web Spray” to your raidframes filter, to quickly know who is trapped in those cocoons. The cocoons are positioned far from the raid (around the walls), so have a range check as well.
The Web Spray will trap everyone for like 10s. During those 10s, you are unable to do anything and everyone takes some damage. This is why you need renew/shield/t2 proc on tank before each of those webspray. You can also spread renews among the raid before each webspray (without dismissing your assign on tank), and when doing so prioritize the cocoond people of course.
After each web spray, top up the tank first and the raid then.
There are also some bugs to aoe, so keep an eye on warlock and magus when it happens.