While it is possible to connect a Phone or Tablet wirelessly through the WiFi Hotspot functionality, using a USB tethering solution is actually recommended. Disabling the WiFi Hotspot will reduce any interference in the reception of the signals from the Air SBC.
Connect your Android smartphone or tablet via USB to the Ground SBC.
Enable USB-Tethering in the options of your smartphone (note, some smartphones don't support this out-of-the box or seem to have this function disabled, you may need a 3rd party app to make USB-Tethering work with your device)
You can now connect using the QOpen.HD app or any other ground control software.