If your iPad model has a Home button, you may prefer to disable it to prevent participants from exiting the application during testing. In this case, we recommend running the device in “Guided Access,” which requires a password to exit an app through the Home button.
To set up Guided Access on your iPad, tap Settings > Accessibility > Guided Access. From there you can turn Guided Access on or off and set a passcode that controls the use of Guided Access and prevents someone from leaving an active session.
To start a Guided Access session, open the app you want to run, then triple-click the Home button.
Adjust settings for the session, then tap Start. If someone presses the Home button, a prompt will indicate that the Home button must be triple-clicked and password entered in order to exit the app.