What are the meanings of the sounds of the Mijia Front Load Washer Dryer 10.5kg?

Here are the meanings of the sounds of the Mijia Front Load Washer Dryer 10.5kg when it is running:
1. When water is filling: When the washing machine is filling with water, the water inlet valve works and makes a "buzzing" sound, which is normal;
2. During operation: The motor of the washing machine will make a "buzzing" sound during operation, which is normal;
3. When draining: When the washing machine is draining, the drain pump works and makes a "gulp gulp" sound;
4. When starting: When the washing machine starts, the door lock closes and makes a "click" sound.