Short Step cross sills and reinforcements?

[ZEKE68]

On a short step, how many cross sills and reinforcement bars should there be, and where are they set? What order. Getting ready to install a wood bed in mine and I don't know how they supposed to be. Mine had a plywood bed in it when I got it. I now have (not counting the very end sheet metal ), two thick sills in front of the axle and a thinner reinforcement bar after the axle then another thick sill before the back bed sheet metal.