The adjuster on the underside is just to prevent the brake band from drooping down when not in use and therefore wearing out the top of the lining. So tighten that one up so that it is pressing the band against the drum, and then back it off the one and a half turns to provide the requisite gap.
Adjust the adjuster that is under the topside cover for actual pedal adjustment of 3-4 inches freeplay.
I don't think you need two people although it's helpful if you do. Adjust the pedal freeplay, then jam a 2x4 or something to depress the brake pedal so the band is tight around the drum, then adjust the underside standoff. Remove the 2x4 and check your freeplay then you're good to go.