TAKING OUT DASH. HELP PLEASE! 89 GT CONVT.

[biglg]

I am taking out the dash of my 89 mustang for the first time. I think I have everything lose. Except the hose that comes from the back of the heat ac gauge. It is a yellow hose that goes to a goldish cylinder, coming out the cylinder is a little arm with a hole. I believe this is opening/closing the vent flap! How do I unhook the hose from the cylinder. What am I supposed to do? I just unhooked the cylinder from the dash, but I dont know if I should have. When I put it back on, is there a certain way the arm coming out the cylinder has to go back on? It rotates around in a circle, so getting it back to the original position seems impossible. Do I have an issue? Please let me know so when I put the dash back in I can make sure I get that correct. Thanks.