Quite simply, look at the sketch below. Two root (or center) ribs, each set at an angle when the wing is built. If the plan calls for a dihedral angle of 2 degrees, then each root rib is set at a 1 degree angle. The result is two degrees.

By the way, as a rudder & elevator only airplane, that Kadet will have a larger dihedral angle than your Superstar. Dihedral helps the aircraft turn when using rudder, so flying your Superstar with rudder and elevator will not be exactly like flying the Kadet.
Dennis-