AveryCharlotte

I see such awesome skin and hair and I wonder.. Is it like Sims where you take the template of the skin and edit it? Do they start over completely and create a new skin? Like this? https://www.youtube.com/watch?v=JYB5zcgpX6Y I'm not sure if this is posted in the right spot sorry if it isn't...and sorry if this question has been asked before and I didn't see it,