You would want to tie each user to a hotdesk extension because it would also tie to their voicemail. So your devices Might look like this (I am start at extension 1000 - but this part is arbitrary since it is only to get the endpoints ready).
1#000, 1#001, 1#002... with IP Device Only service levels.
Then your hotdesk users will have actual extensions (doesn't matter what they are) with a Hotdesking COS and sign in and out of the phones as necessary. Then their keys, voicemail light, and all that other fun stuff will follow them around, regardless of where they might be stationed.
That's a gross oversimplification but I hope gets the idea across.