A couple of posts above mentioned the little pin in the back that keeps the lock cylinder in the sleeve. Once you depress that pin and pull out the lock cylinder (working trunk key required) then the lock rod just falls out of the sleeve through the front opening. Mine are all assembled or I would take some pictures. You can reuse your old lock rod: just take it out and put it in the new assembly. They are rarely damaged.
I don't see any parts you are missing. You have to adjust the strike plate and/or the lock body so that they mate correctly; both sideways and up/down. I do that by laying in the trunk with a flashlight and watching how the parts align when the lid is closed. (Wife, or whoever, may have to unlock the trunk and let you out in the latter stages of this game.
) When correctly adjusted you have to at least lightly slam the lid to get it to latch. Otherwise the lid won't seal tightly on the gasket and keep the water out.
IIRC the retaining pin is in the small hole shown in the left most SD part in your 2nd picture. Also, almost as expected I had trouble fitting the SD lock cylinder to my NOS lock sleeve. My notes: The SD cylinder would not fit the NOS housing without about an hour's worth of filing and fitting to both the cylinder and the housing. Then the SD o-ring (larger than the Ford one) will not fit the housing. Luckily the NOS housing came with a correct o-ring.
I didn't make a note about it, but I seem to remember that part of the filing was to the retaining pin hole in the lock cylinder since the SD pin did not mate correctly to the sleeve. Whether an SD pin will mate correctly to their own sleeve is TBD. You may have to also use your set of Swiss files.
The O-ring is inside the cylinder to keep water from passing through into the trunk. A correct NOS Ford O-ring c1982 measures 0.068 x 0.70". The incorrect SD O-ring was 0.076 x 0.75". They obvioiusly have never seen a correct one. The correct one is a standard 2-016 O-ring!!! Not available in China??
WHY CAN'T REPRO PARTS BE MADE CORRECTLY??