A poster posted a video yesterday about it.
Use of facial cameras, temperature checks at all buildings and the airport, use of other technologies to open doors and reduce contact, mostly takeout only, wearing masks, and tracking all spending. When someone tests positive they notify all family and even vendors to self quarantine.
Despite this it’s difficult because they have really high density and the virus is so infectious. Scary part is the US isn’t doing half of what they are doing. It seems like after China’s initial peak and denials they do now have a much better preventive strategy than us.