Is the body going on for the last time or are you taking it off again for painting? If you are taking it off again you could leave the splash aprons off. Before you put it on for the last time they will need to be in place.
Was the wood frame work built on the chassis? From the pictures it almost looks like the metal is on?
Anyway, I would secure the wood frame work to the body, I used one metal and one hard rubber shim at each mounting point and tighten the bolts. Make sure the frame work is square or you will be fighting it and have serious problems with door and panel fit. Measure all the openings and frame work on the diagonal to make sure.
Then starting at the cowl move backwards attaching the sheet metal. I did not have a Coach or metal roof so we will need more input from others on that.
Lots of posts about this in the past but please keep the questions coming. Here is an interesting project from the 31 Chevrolet site;
https://1931chevrolet.com/restoration/index.htmGood luck
Dave