Use APKPure App
Get Focus old version APK for Android
This app will help you to practice Focus.
We should all practice concentration, without practicing we will never be good at anything so this is how you practice how to focus your mind.
It's actually really simple all you have to do is bring your mind back to a certain point and keep it there as long as you can, and if it slips through you bring it back again again and again.
Hope this was you will master the art of concentration.