Hello Presto.
If you're using 2 servos for the aelerons and 2 servos for the flaps, you can use a Y harness for the aelerons and then, connect the 2 flap servos to additional channels (like 5 and 6) on your radio and work on the mixing for that. If you have a turnigy 9x, look for flaperons, the setup for the mixing will be the same, but you will use 2 different channels for the flap servos.