Stay home as much as possible. Work from home if you can. You should only go outside to shop for essentials (do this alone), to get some fresh air or to care for another person. Always stay 1.5 metres from other people (2 arm's length). Wash your hands often with soap and water for 20 seconds, then dry them thoroughly.
For the most up-to-date information about the virus please see government.nl and The National Institute for Public Health and the Environment (RIVM)