Plug the two connector pins from the radio adapter into any of the aircraft radio plug connectors. Be sure you are using a fixed wing adapter and not a helicopter adapter. Look at the pins and see that there are two different sizes indicating it is a fixed wing adapter.
Plug the cords from your camera directly into the plugs on the adapter. On the other set of plugs at the adapter, plug in the headset pins.
Turn on the avionics switch along the aircraft panel along with the master switch to test the radio connections before going through the pre-flight and engine start-up procedures.