The first step in electronics is understanding the concepts of current and voltage. There is a hydraulic analogy that helps to understand electricity, but here we will try to cover how it works on atomic and electron level.
The stepper motors are constantly pulling current. Without any cooling the chip that is on the stepper driver module would burn very quickly. Adding small heatsinks on top of the chip is of course the first step, but we can go a bit further.
Our 3D printer is finished, but we still can not use it until we program the Arduino board with software that will control our printer. There are several options for the firmware. I have chosen Marlin.
After hooking up of all the connections to the RAMPS 1.4 board we will need to provide power to the board. The standard 5V output of the USB connector is only sufficient to power the Arduino and the LCD display, so we will need external power. The minimum power that needs to be provided is 12V x 20A (240W). But just to be sure we will use a 12V x 30A (360W) power supply.