Solved! How to use overview button to lock an app

[slenzyawumbase]

I want to keep watsap detect always active and I was asked to use the overview button

 

[slenzyawumbase]

MERGED QUESTION
Question from slenzyawumbase : "How to lock an app"

I want to keep watsap detect always active

 

[webworkings]

http/www.tomsguide.com/faq/id-3165946/overview-button-android-nougat.html