The tailgate uses the timber cladding for its strength.
There is a drilled hinge pin on the LH side of both tailgates for fitting a split/cotter pin to prevent the tailgate from being removed from the trailer. This is more important for the front tailgate if you plan to transport long lengths of material with the tailgate down, to prevent the tailgate from falling off.
Cut and drill all the components as detailed below.
The hinge pins require a 6-7mm offset from the hinge strap and with the 9/16" hinge pin, its just a case of laying the hinge strap and pin on a flat surface and tack welding together.
Once all the pins have been tack welded to the straps, position and square the straps to the tie rail and tack weld securely.
Tack weld the latch plate into position.