simple enoughI used a refill kit which comes with a small hand drill, rubber stopper hyperdermic and two bottles of ink.Drill into the top (I did it between the raised part of the cartridge) once you break through inject into the foam with the hyperdermic needle put in the rubber stopper. then insert cartridge in printer lie to the software say it is a new cartridge and off you go. Colour is a little harder i believe because there are 3 ink wells to find. it is a great little printer and fairly economical once you know how to refill :-)