This is a very basic question from a very, very new user of Arduino. There may well be something available but I have searched and can not find an overview of how Arduino all comes together, in particular the firmware/software side of things. I have a Mega 2560, Ramps 1.4 with a full graphic LDC display to use on a home built CNC router. I need a birds eye view of how GRBL, Marlin and an IDE fit together. I sort of understand each aspect but not the overall concept.
Any pointers to the right info would be greatly appreciated.