Replacing the air filter is a routine operation in car maintenance, and the following are the general steps:

1. Prepare tools:
Usually only a screwdriver or wrench is needed, depending on how the air filter box is secured.
2. Locate the air filter:
The air filter is usually located in the engine compartment, in an obvious plastic box. It may be located to the side or above the engine.
3. Open the air filter box:
Use a screwdriver or wrench to remove clamps or screws holding the air filter box in place. Some models may only need to press the buckle to open.
4. Take out the old air filter:
Carefully remove the old air filter. Check its condition, if it is very dirty or damaged, it needs to be replaced.
5. Clean air filter box:
Before installing a new air filter, the inside of the air filter box should be cleaned to remove all dust and impurities.
6. Install new air filter:
Put the new air filter into the box and make sure it is installed in the correct direction, some air filters have a marked side and should be installed in the indicated direction.
7. Close the air filter box:
Reinstall the lid of the air filter box and ensure that all clamps or screws are properly secured.
8. Check:
Make sure the air filter box is completely closed and not loose.
9. Complete:
Pack the tools and check for any missing parts.

The frequency of replacing the air filter depends on the environment and conditions of the vehicle, and it is usually recommended to replace it every 10,000 to 15,000 kilometers, or when the degree of dirt is obvious. Regular replacement of the air filter can ensure that the engine gets clean air, improve fuel efficiency and engine performance, while extending the service life of the engine.