Make a backup plan. Examine the date and size of each and choose the one that is most relevant. The transfer begins after you select a backup.
Sign in with your Apple ID when prompted to restore your applications and purchases. You'll be prompted to check in to each Apple ID if you've purchased iTunes or App Store items with multiple Apple IDs. You can skip this step and sign in later if you can't remember your password. Until you sign in using your Apple ID, you won't be able to access the apps.
Wait for a progress bar to display and complete while staying connected to Wi-Fi. The progress bar may take a few minutes to an hour to finish depending on the size of the backup and the network speed.