Question

Telemetry can be used to communicate with QGroundControl and is very useful especially for tuning for example as parameters can be changed without plugging in a cable each time.

3DR WIFI Telemetry

With the 3DR WIFI Telemetry you just need one transmitter (provided you have a WIFI card/stick in your computer/tablet). Just connect the module to the TELEM port and it should act as a WIFI station.

essid: APM_PIX
password: 12345678

Once connected to the WIFI, it should automatically connect to QGroundControl.