73 Dodge Dart Sport Fuel Gauge Wiring

Hi,

I've read through all the posts about testing the gauge and sending unit, however, my gauge has no wires on it at all just the 2 terminals sticking out the back. Can somebody please tell me how it's suppose to look like. Is there a negative and positive coming from the sending unit? Or just one wire from the sending unit. I followed the blue wire from the sending unit to the underneath of the dash then lost the trail, because it's very difficult to look under there behind the fuse.

Also, my sending unit has only one wire going toward the gauge, is there suppose to be a ground?

Thank you