To clean the filter of a Xiaomi hoover, you can follow the steps below:

1. remove the filter: carefully pull the filter out of the appliance. This may vary depending on the model, but there is often a small button or flap that you need to open.

2. cleaning: Use a soft brush or paintbrush to remove loose dust particles. For heavily soiled filters, you can also use a hoover to remove coarse dirt.

3. water cleaning: Some filters can be cleaned with water. Make sure that the filter dries completely before you reinstall it to prevent damage to the electronic components.

4. drying: Leave the filter to dry for at least two days on a heater or in a warm place to ensure that it is completely dry.

Since I do not have specific instructions for the "G20 Lite" model, I recommend consulting the device's user manual or visiting the official Xiaomi website for detailed instructions.