You have to get up on top of the door click on the door and then open it, which then you have to kill the risen that spawn. The only real problem I had was during the boss fight where the NPC’s died in 1 hit and the spectral guards weren’t agroing properly, I also had a problem with the pillars not stopping anything that went through them. I also had the NPC’s come back to life multiple times during this fight, it was kind of weird.