System UI tuner

[Android Central Question]

Icon is spinning but when I leave it after 5 secs nothing happen.. P20 Lite is the device I'm using

 

[Javier P]

Welcome to the forums. Can you see a tiny wrench beside the settings icon? Also, what Android version do you have? After Pie the UI Tuner was removed from stock Android and you'd need a trick to activate the demo mode.