Setting Firmware for Dual extrution

hello all in all the time I have worked on 3D printers I never put a second extruder on my printers because of the 2 Nozzle issue… now that they have come up with a cheap cyclops clone I bought one… I think its sli3r that’s the problem or Repetier the firmware is showing 2 extruders so this should be working.
I am stumped as to how to get this working??? the unit only has one Heater and one thrmoster… and every time I set dual extrution on the firmware and cyclops nozzle it still thinks I have 2 nozzles.what am I doing wrong??

Hi you should provide more information regarding to your printer and which board you are using …

got it working MKS1.4 TEVO Tarantula running standard drivers 2011 went back to 2.0.0 got it running for a single extruder then just set EXTRUDERS 2 and Uncommitted Cyclops Extrudes
This is all I changed from a Single extruder WTF I know… right?
// This defines the number of extruders
// :[1, 2, 3, 4, 5]
#define EXTRUDERS 2

// For Cyclops or any “multi-extruder” that shares a single nozzle.
#define SINGLENOZZLE