.............You're going to need some steel vertical posts like 2"x2"x1/4" square tubing that will slide down into stake pockets welded to the outside edge of the frame . They will hold up the cattle panels that you install . Then you'll need some kind of steel cross members to connect each pair of vertical posts at their top . You can cut short pieces of 1" pipe and weld them to the 2x2 tubing and use 3/4" rod to slide down into the 1" pipe to hold them together . Then you'll need to build a gate of sufficient strength to sustain the many kicks of cows and bulls can deliver when they're in a bad mood .I have a flat bed trailer that I'd like to build a slide in stock rack of some sort. Maybe out of cattle panels. Any ideas?