A dead battery is one of the most common roadside problems, and jump-starting is safe and simple as long as you follow the cable order correctly.
Position the working (donor) car close enough for the cables to reach, but with the two cars not touching. Turn off both engines and all electrical accessories before connecting anything.
Connect the red (positive) clamp to the positive terminal of the dead battery first, then the other red clamp to the positive terminal of the donor battery. Connect the black (negative) clamp to the negative terminal of the donor battery, then connect the final black clamp to an unpainted metal surface on the dead car's engine block — not directly to the dead battery's negative terminal, which reduces the risk of sparks near battery gases.
Start the donor car and let it run for a couple of minutes, then try starting the dead car. Once it starts, leave both running for a few minutes before disconnecting the cables in the exact reverse order you connected them. Drive for at least 20–30 minutes afterward to let the alternator recharge the battery — if it dies again quickly, the battery itself likely needs replacing.