1. First, check the reason for the falling off of the hinge. If the hinge itself is broken, just replace it with a new hinge; if the screw on the hinge is loose, just replace the screw. It is recommended to replace it. Choose a larger screw and screw it on, so that the hinge is repaired.
2. Hinged installation: Align the hole of the hinge with the hole of the cabinet door, and then fix it with screws. After fixing, try to close the door to make sure that it is correct.