On android operating systems 9.0 and above you may have to unplug your device once the Kodi backup file has finished installing. I have noticed on some devices pressing the home button and force stopping it from within the Kodi application doesn't work. What happens is that the skin doesn't fully install properly so if that happens to you, try doing that.
Kodi Installation Video
Alternate Kodi Installation Video
Advanced Settings xml guide
1gb RAM device - (50mb) xml= 5248800
2gb RAM device - (200mb) xml= 209715200
3gb RAM device - (350mb) xml= 367001600
4gb RAM device - (500mb) xml= 524288000