Hi D
OK, take your big pocket knife and run it in the slit to cut loose the piece on the top bar. You can cut it off before or after you put your frame together.
Then slide your foundation into the bottom groove and place the piece you have cut off back where it was, securing the top of the foundation to the top bar.
THen nail or staple the piece you have cut off to the top bar. There are two ways to do this. You can either nail through the foundation or nail it into the top bar from the bottom.
I like the latter method better because then if you have to replace the foundation you can get the old foundation out without destoying the frame.
I also use 5/8" staples to put this in with an air compressor and staple gun. WIth a little practice you can do it pretty easily.
Hope this helps. It is easier to do it than to explain it!
[ March 27, 2006, 05:37 PM: Message edited by: BerkeyDavid ]