1. Make sure you have turned on the mobile printer and connected to it in your phone's bluetooth.
2. In driver app go to Settings by clicking hamburger icon in top right and Settings.
3. Connect to mobile printer by clicking "Connect".
4. Click Test Printing button to make sure printer is connected.
After marking delivery as done, the page in the image below will show up. Click Print. Currently you can only print one tag at a time.