If you have the full set of instructions they should give you the order in which to do things.
From memory of building the original Aerokits, I would have put the side wood on first, so that the final joint between the two skins would be covered by the rubbing strakes. But with modern glue this is probably less important. Do put the deck on last, however - you don't want to have the edge of the ply sides visible around the outside of the deck.
Does the Sea Rover have a balsa block at the lower bow? If so, you only need to bend the wood round onto the first former, and there will be very little trimming needed, just around the keel. You glue onto the keel and the chine, overlapping the chine, and only trim the outer part of the wood back to the chine when it is dry and hard. Similarly for the hull sides - sand the formers and chine to a flat surface, then glue the wood overlapping the chine and deck, then trim once dry.
If the kit has no balsa block and you have to fit the skin precisely to the hull, it can help to make up a cardboard
or paper template first, to get the shape close to accurate. One technique for final shaping involves positioning the skin along the straight part of the keel, securing it at the transom with a small wood screw, and then swinging it round to match against the bow, swinging it back out to sand down the high spots, and then swinging it back to check the match again... Soaking the sides for an hour in warm water, or steaming them will also help them to bend easily. If you soak them, pin them in place without glue and allow them to dry overnight - they should then be easy to unpin, add glue and reassemble.
For the side you will need to cut the ply sheet so that it locates nicely along the stem. The original kits had a set of small brass 'gimp pins' to hammer in and hold the wood in place - modern glues will probably hold well enough without these. But you will need clamps, rubber bands
and blocks of wood to keep an even pressure on.
Watch out to avoid twisting the hull. Check that it is built straight at the moment, and then put the wood sides on as a pair to lower stresses. If the hull is already twisted, you may need to losen some of the chines and reglue!
Looking at the pictures, it seems to me that the piece of wood which acts as the rebate on the stem may not be accurately fitted - it looks as if the top is a bit far back. And it also looks as if the motor shaft is not precisely in line with the prop-shaft. These may just be artefacts of the picture, of course. But if they are really as I have suggested, now is the time to correct them, before the sides are on. I would also glue the prop-tube onto the former it is going through for extra support....
1 - check build quality and amend if necessary
2 - confirm internal hardware (motor, rudder and R/C) is properly in place.
3 - add the wooden hull bottom and sides
You might like to draw planking lines of the deck before adding that? Although I hear that in some modern kits these are pre-drawn...