What's the process of clay pressing?

Hello, seeing a bunch of people making kirk sculpts with a clay press life cast has got me wondering how they do it. How do you clay press a life cast? I’m asking this because I wanna make a Myers mask.

A mold is made of the face and clay is poured into it, and a base is built on that, correct me if I’m wrong

A rubber or alginate mold is made of a plaster Shatner life cast. From there, modeling clay is headed to a liquid state and poured into the mold, replicating the life cast in clay. The new clay life cast is added to an armature and the rest of the sculpt is built around the life cast and then modified to make the sculpt fit whatever look the artist wants. Then it’s molded in a 2 piece plaster mold, and then latex can be poured to form a mask blank.