>>312986023
its very easy, you just take your avatar/world make a copy of your project folder, upgrade to their unity version, see: 
https://cck.cvr.gg/

wait a bit for it to upgrade, remove vrc sdk, put in cck sdk, add their avatar descriptor, rest is intuitive and familiar. same with worlds.

They have 3 video tutorials too, 5 min total:
https://www.youtube.com/channel/UCl8toTHzEER6PXoJyZcTFjg