normally u shouldn't need to manually adjust the drums self-adjuster mech cos it's um self-adjusting, but the threads do become clogged n seized with brake dust over time.
whenever a drum brake is serviced, you should always:
take out the self-adjuster,
unscrew the ratchet cog off the shaft,
clean dirt/grit off every part with brake/carb cleaner then retap & die the threaded shaft and ratchet cog to make sure they screw in/out smoothly,
suggest avoid copper grease on the threads cos it'll only attract brake dust n clog up again so I used graphite powder instead,
screw the ratchet cog all the way into the threaded shaft so its as short as possible,
reassemble brakes,
retighten the handbrake cable end nut till there's no free-slack before the 1st click,
then apply the handbrake several times to ratchet the self-adjuster (in a quiet garage you'll be able to hear it click to the next cog after each pull)
keep pulling until the clicking stops, now the adjuster is set so it's 1-ratchet click away from the shoes touching the drums.