Have you found the release yet? I could post pics of mine, different brand but probably the same idea.

When I picked up Flossie after the shop reassembled her, I had to go BACK and ask them to show me the quick release, cuz I couldn't figure it out to load her into my car.

The center wire that connects the two arms has one end (on mine, the left) that is firmly attached, and the other end (right) has a round barrel-shaped stopper on the end. When I squeeze the arms toward each other, and get some slack in the center wire, I can pull the barrel-stopper out of the right arm.