The lower cowl and upper cowl come together under where the A pillars attach to the upper cowl. Weld up any voids
or holes in the cowls. You should stagger the A pillar sections I sent you to retain strength in them. The hinge pillars should also be in place as that is what the 2 cowl pieces attach to. You should also have the doors on the car for
fit. Remember everything will have to be sealed against moisture. Tack parts for fit before final welding. It is imperative to have the doors on the car to check for fit because you don't want to a big fat tomato worm to deal with.