Safely remove the battery terminals in the right order so you avoid sparks and short circuits.
Switch off the engine, lights, and accessories, and remove the key or fob. Put on safety glasses and remove rings or metal watches that could bridge the terminals.
Find the terminal marked with a minus sign or a black cap or cable; it is the ground. The positive terminal is marked with a plus sign and is usually red.
Loosen the negative clamp nut with the correct wrench, lift the cable off the post, and tuck it aside so it cannot spring back onto the terminal. Always do negative first to prevent shorting against the body.
Loosen and lift off the positive cable next, keeping the wrench from touching any metal while it is on the positive post. Set both cables clear of the battery.
When you are done, reattach positive first, then negative, and snug each clamp firmly. Note that disconnecting may reset clock, radio presets, and learned settings.