How to change back to the default wallpaper?

“To change back the default wallpaper, please:
1. Tap on APUS Wallpaper’s icon;
go back to the default wallpaper-1

2. Tap on “”Mine”” which is on the bottom right corner of the screen;
go back to the default wallpaper-2

3. Select your favorite wallpaper and set it;”
go back to the default wallpaper-3
go back to the default wallpaper-4