1. Unlock the iPhone and click Settings in the main interface, as shown below.

2. Click the auxiliary function in the settings, as shown in the figure below.

3. Click Touch on the accessibility interface, as shown in the figure below.

4. Click the auxiliary touch tab on the touch interface, as shown in the figure below.

5. Click to open the switch behind the auxiliary touch, as shown in the figure below.

6. Open the auxiliary touch, and click the custom top menu, as shown in the figure below.

7. Enter the top menu setting interface of the auxiliary touch function and click Customize, as shown in the figure below.

8. Select Lock Screen from the function list and click Finish, as shown in the figure below.

9. Click the small white dot for auxiliary touch, and click the lock screen button to lock the screen, as shown in the figure below.