originally there were metal tabs/clips that attached to the channel by pointy protrusions sticking out one direction that 'jammed' it into the space in the door, 4 of them - otherwise the shape and length keeps it in place .... if you're missing those clips, about all you can do is screw it on using very small flat head screws in the bottom of the channel, don't need many, mainly across the top and toward the top of the front and back to hold the curves, the bottom parts can't go anywhere
Bill
