You don't need to prefix anything with a 7 and there's no video from us that's saying this.
Set up your connection using the Quick Setup. After that, you can transmit your calls to TG9. Make sure it's set as the TX contact for the current channel on your transceiver. You can find more information on cross modem modes in the user manual at
http://manuals.sharkrf.com/openspot2/en/cross-modem-modes.html