1. Take the iPad3 as an example, light up the screen of the iPad3, find the "Settings" option on the desktop, and click Enter.

2. In the setting interface, open the "General" option and click the "Accessibility" option.

3. Find the "AssistiveTouch" option selected in the red box and click to enter the next step.

4. Turn on the switch in the "AssistiveTouch" option bar to complete the touch screen button setting.