I need help with Back Up

I think what you mean is you need help with restoring a backup.

Click on this link to discover how to 'Restore your iPhone, iPad, or iPod touch from a backup' --> https://support.apple.com/HT204184

or watch this video if you're using a Mac to do this:

https://www.youtube.com/watch?v=Jbp3gGTQygg

See if anything here helps

Backup couldn’t be completed or you can’t restore.  *

Backup couldn’t be completed or you can’t restore (2).  *

Backup couldn’t be completed or you can’t restore (3).  *