How to set the automatic drainage of Smith water purifier

I want to decide. The company's Smith water purifier, users only need to twist the outlet valve to adjust the outlet water. Products span two major fields: household products include AI-LiNK professional cold, warm and feng shui integration system, water heater, central domestic hot water, heating stove, water purifier, cooker, central air conditioner, central domestic water purifier and air purifier, and commercial products include water heater, hot water boiler and water purifier.