On some handbrake systems, a primary cable runs through a pulley on the rear axle to a relax lever, which operates the brakes through a secondary cable. It adjusts at the lever.
Another type of handbrake has a single enclosed cable, called a Bowden cable, which runs directly to one brake drum and operates the other by means of a transverse rod.
If you have tightened the brake shoes so that there is no excess travel before they come on, yet...