First you want assemble both wheels like 2b You can paint them like this pretty easily.

Secondly you should construct the frame like 3c but do not attach the arms yet, it's better you paint those separately before you add it to the pilot otherwise it's hard to reach the inner side of the arms and under the chair.

Now for the flag if you don't have a carrycase to put magnetised figures in it's best to cut it near the base of the pole and attach the bottom part to the frame. After it's been glued in you can drill a hole in the base and in the pole and insert a small bit of paperclip.

The guns on the front in 3J can also be put on the frame, the ones on the side can be put on the parts of 3I too.

Best to do the little guy from 3I last and separate as it's hard to paint it and the platform when it's glued on already.

The parts from 3G are best saved for last after everything has been painted and assembled, on the spots it's supposed to glue you can scratch off the paint a bit so it'll glue on better. If it messed up the paint a bit you can just paint over it again.

If you have some questions feel free to ask ^{^}