Like the above posts said, assembly can be very difficult, which is one reason why my Sporty doesn't get disassembled more than once a decade. At one point I had to use a jack to force the center of the deck up high enough to hook onto the top of the rib at the rear of the cockpit.
As best I recall the process:
1. Unroll the skin the the hot sunshine to help make it a bit more flexible.
2. Attach the front three (I think?) ribs to the forward assembly, and the last two (I think) ribs to the rear assembly.
3. Slide the forward assembly into the front of the skin, and the rear assembly into the rear of the skin.
4. Interleave the metal plate in the center of the cockpit floor, and stand on it, this forces the front & rear assemblies into the ends of the skin.
5. Insert and attach the rib at the front of the cockpit (number 4?) and the one at the rear of the cockpit (number 6?). I would NOT attach the runners at the forward and rear peak of the deck yet.
6. Insert the six short aluminum tubes in the cockpit area. This is in my experience one of the most difficult parts, as the tubes don't fit particularly well, and the metal sliders frequently get jammed.
7. Attach the wooden runner under the peak of the deck to the ribs at front and rear of the cockpit. This can be very difficult, as I said I once had to use a jack to force one up high enough.
8. Insert the 'U' shaped rib and the rib with the seat. Getting the side aluminum poles to seat properly can be difficult, on mine the holes for the little brass hooks no longer align with the ribs.
9. Slide the cockpit gunwales onto the bead along the edge of the skin. The holes at the ends of the gunwales are to seat the pins on the brass fitting of the ribs at either end of the cockpit. Once the pins are seated in the holes, put the cast aluminum fitting over and hold it down with the brass T-bolt.
10. Slot the four brass clamps on the gunwales through the holes in the brass fittings of the two ribs in the cockpit (the U-shaped one and the seat rib), then turn 90 degrees and clamp then to the gunwale.
11. Swear that you will never, ever take the darn thing apart again!