This is a simple kiosk app that I use with a wall mounted iPad for my home automation setup.
It displays a main web page and optionally a screen saver web page.
I use it to control my SmartThings devices (using ActionTiles), along with a screen saver (using DAKboard).
Tap the screen saver page to dismiss it and view the main display.
The Settings page is visible whenever the app is brought to the foreground.
To enable Guided Access:
Settings > General > Accessiblity > Guided Access
or ask Siri to 'Turn on Guided Access'
To prevent the screen from sleeping:
Settings > General > Accessibility > Guided Access > Mirror Display Auto-Lock > On