Okay. When you mentioned flaps, I assumed you had separate flaps and ailerons on the wing, if so, I'd use the "Y" connector and plug both servos into the flap channel. Not sure which that is on your radio, but likely channel 5.

If you don't have separate flaps on the wing, then yes, you'd have to use "flaperons" and two servos plugged into separate channels. Likely 1 and 5 or 1 and 6, then mix them in the transmitter. Do you have the manual? It should tell you how.
Dennis-