Maybe I’m dumb but I can’t back up my notes toa different date on my I pad

Perhaps you are trying to restore an existing Note to an earlier version?

Unfortunately, unlike some other Apple Apps, such as Numbers and Pages, the native Notes App does not maintain a version history; as such, you cannot restore a Note to an earlier point in time. However, if you have enabled Notes in iCloud, it is possible to restore a deleted note:

Delete and recover notes on iCloud.com – Apple Support

What does “to a different date” mean?

The Notes app displays the date a note was last modified.