Expert mechanics take years of practice and extensive experience. It is best to learn how to fix cars under the supervision and guidance of a professional mechanic.
You will be required to spend time at a car garage learning as much as you can about cars. It is important to get familiar with the mechanics of cars and engineering.
You will also need to go to auto school.
The most important thing is to start early. Do not wait to learn automotive technology. You can get certified as a mechanic by getting started right away!