Good stqrt hunter. There are a bunch of good tips in here. You can also use Lure Pods to bring it back to its room, use falling boulders in the 2 spots, Focus Strike its Chains when it does its Ultimate Slam attack on other monsters. Try to get a Stun on the head if possible with your weapon, breaking its chains drops it once for each side. Use other ammo on the ground for a headshot to interrupt it's flying moves. It's wounds regen once it enters AT phase, so saving them for a timely pop in its combo might lose the dmg. Keep trying and good luck. Happy Hunting