Chock wheels, and try to do this on level ground with tranny in neutral.
Forget adjusting until you remove drums and take a look.....odds are you'll discover rusted/seized adjusters or more, so first take a look. (I'm assuming these are drum brakes)
Back off the adjusters nuff to drop them out, then disassemble them and wire brush the threads and reassemble with brake grade anti-seize and thread lube. They get really hot and are subject to corrosion so use lube designed for it....Check all other hardware and adjusting cables-replace as necessary....wash whole assembled unit(not your freshly rebuilt adjusters) with brake clean, then adjust shoes outward til you can just slip drum over them.
Once drums and wheels installed, use brake adjusting spoons to adjust each side tight, then stomp on the pedal a few times, then back off each side to where you hear a VERY slight drag...just a tad of drag.
Go drive it....fwd a few feet, then reverse several times, each direction apply the brakes firmly several times....Ok, you're done