Good luck.
7-6 should have a fairly friendly observer who should give you lots of advice.
Play your normal game, listen to him post-match, don't be afraid to ask questions if it will help your understanding on a matter or clarify something further for you. They're there to help you (or they should be anyway), and this is a fantastic opportunity to ask questions, something a lot of referees fail to take the opportunity to do.
Otherwise, for the match itself, pretend he isn't even there and referee as usual and enjoy the game.