The unit will not automatically display a Navionics map upon insertion of the card, after inserting your card you must select a “Navionics Map Choice” before the lake will be displayed. Install the card and turn the unit on. From the Map Page, press Menu then select Map Data. On the Map Data screen you will see “Navionics Map Choice” above a drop-down box (the drop-down box will probably contain “Lowrance”). Scroll down to “Navionics Map Choice”, hit enter then open the drop-down and select one of the map names from your Navionics card and hit enter again. Exit back to your Map Page and you should be good-to-go.