How do you replace auto battery for 2003 Passat 1.8 turbo?

To replace the battery in a 2003 Passat 1.8 Turbo, first ensure the vehicle is turned off and the keys are removed. Disconnect the negative terminal (black) first to prevent electrical shorts, followed by the positive terminal (red). Remove any securing brackets and lift out the old battery. Place the new battery in the tray, connect the positive terminal first, then the negative terminal, and secure everything back in place.