How do I delete some of my backup?

Hi TimberPark,

Thanks for using Apple Support Communities. It sounds like you want to manage your Apple Watch backups. Deleting only partial backups isn't supported, but you can see what is included in backup here: Back up your Apple Watch

If you want to delete previous backups in full you can do that with the paired iPhone in Settings > General > iPhone Storage > Watch and scroll down to find previous backups, including the date it was completed and the size of the backup.

Thanks