I have just put together my Hictop Prusa i3

I wanted to add a 2nd extruder to my Hictop Prusa I3.
I bought a Geeetech MK8 Dual extruder e3d and I use Simplify3D for my slicer.
I don't see anything about a Dual extruder Reprap type firmware listed in it.
I cannot find any thing to tell me how to update the firmware on the 3D Printer Control Board MKS Base V1.3 RepRap Arduino-compatible Mother Board.
I did download and am going to print out the bracket needed to put the dual extruders in place, but can not find anything on what firmware I need and where to get it.
I would appreciate any help.
Thanks

well as far as s3d profiles go - ask on the s3d forum. The guys over there are pretty good.