Turn on Guided Access. Go to Settings > General > Accessibility > Guided Access, where you can:

• Turn Guided Access on or off
• Set a passcode that controls the use of Guided Access and prevents someone from leaving a session
• Set whether other accessibility shortcuts are available during a session

Start a Guided Access session. Open the app you want to run, then triple-click the Home button.

Adjust settings for the session, then click Start.

• Disable app controls and areas of the app screen: Circle any part of the screen you want to disable. Use the handles to adjust the area.
• Enable the Sleep/Wake or Volume buttons: Tap Options and turn on the buttons.
• Ignore all screen touches: Turn off Touch.
• Keep iPhone from switching from portrait to landscape or from responding to any other motions: Turn off Motion.

End a Guided Access session. Triple-click the Home button, enter the Guided Access passcode, and tap End.