Hi, I'm new too. I have a Magellan 315, so I don't know if it works the same, but last week I asked and this is what someone told me.
Turn it on. Menu Setup. Check that the Primary chart datum is set for WGS84 and Primary Coord system is set of Deg/Min.MMM Press Mark then Enter and edit the Waypoint to the Cache Name by scrolling through the alphabet. Scroll down to the coordinates. Enter and edit the latitude and longitude to the cache site Lat and Long. Scroll down to Save. Press Enter. Press the NAV button until you get the Compass Screen. Press GOTO Highlight USER and Enter. Highlight the cache waypoint name you just put in. Enter. The Compass will now point to the cache. Follow it until the distance reads 0 and you should be right there. This worked for me. I've found 2 caches the past 2 days.
Julia Scott