Cnotbush streams himself sculpting clay figures and statues daily on twitch
Ace of Clay, Dr Garuda, Art Chong, North of the Border, Sculpture Geek, etc all post sculpting vids on YouTube.
Some use a polymer clay you bake to harden, some use plasticine based clay that never dries. Depends on the artists preference and needs.
When I was in high school - ages ago - one of the substitute teachers of my art class was sanding/polishing their marble bust they were working on. It was neat to see the process but it’s really just a lot of wet sanding once past large removal / chipping.