Hey Terry. I believe the "Miller site" has a PDF tutorial that explains the whole process. Some of the structures are plastic and some are a light gage metal. I have both.
Here is what I do...
I build the support. Then I lay the sign flat on a piece of glass or something that will not attract the ACC. I position the frame on the sign and then "tack" into place with a few drops of the super glue. Then I hit it with a spritz of the "instant set stuff" (technical term) that immediately hardens the glue dots. Place on layout and plug it in.
That is it..no need to apply a lot of adhesive.
Hope that helps.
Donald