Triple slotted flaps on a 2 metre wing span 737 model? You are having a Steffi Graf mate. The classic system is cable driven with cam wheels moving the actuator rods to push the fore flap and the aft flap away from the mid flap. there is also the exhaust flaps ob the inboard and outboard flaps. NG system is easier, without the exhaust flaps and is rod driven, with bellcrank linkages. Good luck designing your minature..