Be careful that you don't allow the two clamps on your jumper cables to touch once they are attached to the good battery. This will cause sparks and can damage your good vehicle. Attach the jumper cables one at a time to the bad battery. Match the red wire with the red attachment on the battery and the black with black.
Step away from the vehicle. Turn on the good vehicle, letting the bad battery charge for a few minutes. Try to start the dead car after one to two minutes to see if it will start. If it does, the jumper cables can be removed.