wear to get my contact that's was back up

See the instructions in this document:

If you accidentally deleted your calendars, bookmarks, or contacts from iCloud - Apple Support

You say you have a backup but not what kind. Restoring things from a backup requires erasing the device and reverting the entire device to the condition it was when the backup was made.

1. On the Home screen, tap Settings.
2. Tap your Apple ID at the top of the list.
3. If prompted, sign in with your Apple ID.
4. Tap iCloud.
5. Tap Contacts to switch the slider ON.
6. If prompted, select to Merge contacts with iCloud.
7. Tap the iCloud Backup app at the bottom of the list.