How can i restore from old backup

Read/watch these links -->

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

Some things are not stored in a backup. Click on this link and read "About missing information after you restore your iOS device with iCloud Backup" -->

https://support.apple.com/HT203768

Please follow the steps at Restore your iPhone, iPad or iPod touch from a backup – Apple Support to restore your device from a backup.