I don't know the exact location for the CG of that specific plane, but most people fly with their CG about 30% back from the leading edge of the wing. It should also give you the exact location in the manual that came with the plane.
I'm flying my Ka-8 with the CG 65mm behind the leading edge of the Wings.
You can see the two first flights of my Ka-8 (Hi-start) in the following video: