Connect via cable to the computer that you use for sync. From iTunes, select the iPad/iPod and then select the Summary tab. Follow directions for Restore and be sure to say "yes" to the backup. You will be warned that all data (apps, music, movies, etc.) will be erased but, as the Restore finishes, you will be asked if you wish the contents of the backup to be copied to the iPad/iPod. Again, say "yes."