Not that critical,as proper crosshatch lets the rings rotate.
Here goes.
Oil ring ... Rear piston - separator butt faces front piston.
Front piston - separator butt faces rear piston.
stagger the oil ring support rails about 90 degrees in both directions from butt of separator.
Second ring ... Rear piston faces the rear of the motor/bike.
Front piston faces front of motor/bike.
Top ring ... Rear piston faces front piston.
Front piston faces rear piston.
Be carefull that a ring doesn't get caught in the ring compressor,forcing it out of the ring groove.Pay attention to markings on the rings(this side up).
John