From the Settings app, scroll to Accessibility.
Tap Accessibility.
Tap Interaction and dexterity.
Tap Universal switch.
Tap Add switch.
Follow the on screen steps to set up your preferred switches. For this tutorial, we will be using Camera switches.
Tap the Universal switch switch to ON.
Tap Allow.
Tap Turn off.
Using your selected universal switch, tap OK.
You've completed the steps!
