1. Open the Settings to the Passcode & Fingerprint menu, and select Fingerprints.
2. Select Add A Fingerprint. You can choose any finger you like — and even enter multiple fingers — but it’s best to choose one that you’re most likely to use when holding the phone.
3. Place your finger on the Home button without pressing it down. You will have to touch the button several times; as you do, the gray lines will turn red. When all the lines have turned red, the setup process will move to the next step.
4. Adjust your grip so that you’re holding the iPhone 5s as you would normally.
5. Roll the edges of your finger on the Home button. This is so the Touch ID sensor will be able to identify your fingerprint even if you don’t press it the same way every time. Now you can unlock your phone just by using your fingerprint.
6. Press the Home button to turn on your iPhone’s screen. This will bring up the lock screen.
7. Rest your finger on the Home button (you don’t need to press down on it) to unlock your iPhone. If you want to add additional fingerprints, repeat the steps above.