Are you saying they use GitHub (via the web editor?) but have never heard of Git? or don't know how Git works? or just don't know the Git CLI? or something else?
My experience with younger folks that have never been outside the Windows world has been that it was a lot harder to make them understand. Young folks with a unix-y background were much easier.
https://git-scm.com/book/en/v2/Git-on-the-Server-The-Protoco...
".. you don't have to keep the previous versions, so it saves space? OK... No, I was talking about the real git."