In the article someone linked below I found this section :
Archaeologists preserved the newly discovered remains using a variation of a technique developed by Italian archaeologist Giuseppe Fiorelli in 1863. The process involves pouring liquid chalk into cavities left by decomposing bodies; this plaster fills gaps in preserved bones and teeth, creating a cast of the bodies as they looked at the moment of death.
So you find a cavity with bones and other remains in there and use it as a mold I suppose? They probably were excavating the city from the ash cover and when they found something that could be remains of a human they stopped digging and used said techniques to preserve the remains.
Okay, so you're not upset, but still didn't bother to find the answers for him.
Let's just say you did decide to answer him though, what would be the very first thing you step you'd take? Would it be "type those questions into a search engine"?
I understand asking questions when answers might be complex or you're actively involved in a conversation with someone knowledgeable, but I'm tired of this deliberate helplessness on social media.