74 Dart Seatbelts, how do they work correctly?

This is like the last frontier for me unless I'm missing something but I cannot for the life of me figure out how to get the seatbelt to feed from the car so I can put the things on! I did however pull the covers off where they go down by the seats so I can pull the bar in them to let me pull them out but no passenger will ever figure that out in the event of a traffic stop. Is there a trick to them or should I find different ones to put in it or ?. My old trucks belts work fine and are easy to use yet my Dart belts are impossible. The mechanism inside them looks brand new, no rust just as bronze/gold looking as a new one yet they don't work so good. I think I read somewhere that the belts changed to this death trap in 74. Figures! Anybody have any solutions?