The thing that confuses people here is that the way to do it is from within Google Drive, not from your phone's home screen. So open the Drive app on your phone, open the Drive file you want to create the shortcut to, and then go into the settings/options menu from there. You'll see "Add shortcut to Home Screen" option and you can click that to make it. Then exit out of the Drive app and look around your phone screens for wherever it put the shortcut badge and move it around to where you want it.