Backside of drum at bottom is rubber plug(s)
Use strong pin point flash light beam to look inside
Star Wheel for adjustments
IF self adjusting there will be a 'plate' that is attached to a cable ...plate engages star wheel---moving it when brakes are applied (braking when going forward)
You will have to push the plate away/disengage it from star wheel in order to manually move star wheel
No plate...then brakes are non-self adjusting
Info with vid/pictures