It is relatively simple to wire up the RAMPS. Just add the extruder heating coil wire to D10, the thermistor to the two T0 pins on middle right right, and wire up the steppers and endstops. From left to right, wire all of the stepper motor's wires as red, blue, green, and black or red, green, yellow, blue into the pins next to the Pololus. When you connect the wires to the endstops (if you are using 3 endstops, plug them into the MIN (-) slots), make sure you match the labels.