Instructions to pin screen on Fairphone devices

How to protect your privacy when lending a Fairphone smartphone or tablet to someone else. Instructions for setting up "screen pinning" on a Fairphone brand device. Block an application on the screen from which the user will not be able to exit without knowing the unlock pin, in this way you will prevent them from seeing your messages, photos and private data that you do not want to show.

Fairphone 3+ Fairphone 3+
Fairphone 3 Fairphone 3
Fairphone FP1 Fairphone FP1
Fairphone FP2 Fairphone FP2
Fairphone FP1U Fairphone FP1U