Basically, the pickup will typically have two wires coming from it, connected to the potentiometer(volume control) or the switch. One wire goes to a pin on the pot(or switch), the other goes to ground. All you have to do remove one pickup and connect the other(putting the wires of the new where the wires of the old were). There are always issues though. Some pickups use different color wires for ground, some have 4 wires instead of two...the list goes on. So I don't have enough space to explain it all. Search this site and the web to learn all the details. You'll get it.