What is the tone of how to jump start a car battery mean?

The tone of the phrase "how to jump start a car battery" is instructional and informative. It is conveying a way to help someone whose car battery has died by explaining how to connect jumper cables from a working vehicle to jump start their engine. Jump starting a car involves connecting the dead battery (often with low voltage) to a working battery. It is often referred to as boosting someone's car.