You are infected with the coronavirus. To prevent further spread, you need to go into home isolation. You are obliged to follow a number of rules during your quarantine. The rules can be found here: https://lci.rivm.nl/covid-19-patient-EN
You may soon be contacted by the Dutch Health Services for contact tracing purposes. Share your results with your immediate environment and people with whom you have recently been in contact. Quarantine does not mean that you are on your own now: ask for help from your loved ones and / or your doctor if necessary.
For further questions you can call the national number of the Dutch Health Services (GGD) 0800-1351, or the local GGD for the ‘Haaglanden’ area 088 35 50 100.