How does a circulation control helicopter work
A quick scan of the linked document suggests that they're referring to controlling the relative amount of engine exhaust directed into each rotor, which (due to the downward direction of the exhaust jet that drives the rotor) controls how much downward deflection each blade gives its airflow.  By making this differ from one blade to the other, the rotor can be tilted without twisting the blades at the root as would usually be the case with large, heavy lift rotor designs (the effect is somewhat like the Bell-Hiller paddle system often seen on small helicopters).

The resultant rotor tilt gives pitch and roll control, which are used (directly, or by mixing rudder effect) to move forward, aft, or sidewise in hover, and to control speed and climb/dive, plus turn, when in forward flight.