Lock the screen
{{ lockNote }}
1 · Make it a full-screen app
In Safari tap Share, then Add to Home Screen. Open Phonics Trail from that icon: no address bar, no tabs.
2 · Lock them in with Guided Access
Settings › Accessibility › Guided Access, turn it on and set a passcode. In the app, triple-click the side (or Home) button and tap Start. Triple-click again and enter the passcode to finish.
Android: Settings › Security › App pinning does the same job.