How do I CMD/CLI to either inherite theme or copy #198

This is ridiculous. Using Grav CMS. Alright, I want to either inherent the quark theme, or at least copy it.
I use warpline hosting. I can FTP into powershell, but bin command does nothing. SSH nothing, says 'connection reset'.
Really not sure what I am doing wrong. Little help. I tried to copy quark, and just upload it differently named, but it will not show up in themes.
Obviously I don't even know how to use devtools. As a gui plugin or otherwise. Little help, thank you.

And to confirm, yes I used the grav cms tuts (okay found the manual part. Will try this)(. They dont tell me how I can CLI.