Whether it is a canard or anything that flies the longitudinal aerodynamics of the airplane have to end up to 0 at the center of gravity. With the canard planform it is still a matter of positioning the CG such that the lift from the canard times its moment arm to the CG is equal to the lift of the wing times it moment arm to the CG. Once the balance of moments is made you have an airplane that will fly. If the Neutral Point of the airplane (basically the center of the aerodynamic forces) is aft of the CG then the airplane will be stable. Put the canard at a higher angle relative to the fuselage than the wing is set at and you will have an airplane that will trim out at some airspeed to give level flight.

Then the control question comes in. A conventional moveable elevator on the rear of the canard surface will allow changes in lift to be made. Elevator trailing edge down gives increased up lift on the canard. This results in a nose up pitch rate and just reverse the control movements for nose down.

Along the same lines an up flap on the wing will give a nose up on the airplane but at the loss of a lot of lift. Normally on an airplane when you want the nose of the airplane to go up it is to make the airplane to go up also. Loss of lift in that situation is not a good thing!! So the movable surface is put on the front surface.

It is a neat thing the way things work out.