Next, iTunes will display the list of iPhone backups that you can restore your iPhone from (in most cases, this will be only one backup, but in certain circumstances there will be more). Choose the back up you want to use – based on its being the most recent one or the only one – and continue.
Once the proper backup file is selected, iTunes will begin reloading the backed up data onto your phone. The process is fairly quick because it only transfers data and settings, not all your music.
After the process is complete, double check the settings on both your phone and in iTunes for what gets synced to your phone. While the feature is good, it often leaves out some settings, including some music sync settings like podcasts, email sync settings, and other items.