Captain H'Bri is linked with Lieutenant Grauf Thundersmash and not agro at the start. You clear the room of the golem adds and then go to take the portal.
When you enter the room, head to the right and take the portal to a different room. Clear all the golems. Once the golems are dead, split the raid as you see fit to have some in the golem room and some in the Captain's room. When you pull the Captain she will emote and tell the Lieutenant to check the golem room for invaders and the Lieutenant will respawn in that room. Once you engage, you will no longer be able to use the portal until the Lieutenant is dead, so make sure everybody is in position and ready to go.
Kill the Lieutenant. Once he is dead, use the portal to return to the Captain's room and kill her.
Each mob is a simple tank and spank. There seems to be a physical and elemental aoe that are proximity based, but I dont have names.