Using the Abaco Glass Vacuum Lifter DVL 400 is easy. First, make sure the device is fully charged if you're using the battery - operated mode. Then, position it on the glass surface firmly. To move the glass, use the controls to activate the vacuum pump and lift it. When it comes to rotation, just operate the controls to turn it 90 degrees left or right as needed. Note that you should always work within the workload limit to avoid any damage to the device. Also, keep the power source in good condition. For maintenance, regularly check the vacuum pump and battery. Clean the contact surface of the lifter to ensure a good seal. If you have any questions, call for professional help.