No doubt we all have a somewhat different sequence for reassembly, but here's mine: Assuming you are referring to a '36 coupe and that your chassis is largely complete (powertrain, radiator, wiring, instrument panel, etc. all installed) and that your headlining, seats, and upholstery trim panels are all installed, normally the running boards would be be installed next, before the front fenders and the rest of the front end sheet metal. All of the fasteners for attaching all of the fenders and running boards should be just finger tight to permit some wiggle room for alignment adjustments.
Hopefully you installed your deck or rumble lid before you installed your rear fenders
If not, and you also install your running boards before the interior is largely complete, you will come to regret having done so as you've increased the amount of reach necessary to access the interior and deck openings.
