Make sure your range finder is ON. You should see the cross hair.
To change between Yards and Meters just press and hold the "MODE" button.
To change between the G and Target mode press and hold the "MODE" button *AND* within a second or so, press the "POWER" button.
I think this is a bad design because it is easier to switch between yards and meters than it is to switch between G and Target modes. I never switch between yards and meters but I always switch between G and T modes and it takes me a couple of trials before I succeed.
Linkback: http://www.gameandfishnetwork.com/smf/index.php/topic,80.0.html