Beginner guide to editing Marlin firmware step by step UPDATE IN DESCRIPTION

UPDATE: Much of this is relevant, but you can no longer use Arduino to easily compile for 8 bit boards. Fortunately VS code with the Auto Build Marlin extension makes it better than ever. Full guide here: By request: a beginners guide on editing Marlin 3D printer firmware. This video explains what firmware is, the differences between firmware source and compiled firmware, where to get the firmware and editing software, basic concepts, specific scenarios, uploading and troubles