First and foremost: stay calm
If you are a confirmed contact the health department will contact you by telephone within 48 hours
If you already have typical symptoms such as fever, you should, as a precaution, stay in domestic quarantine and inform the health department.
A variety of constantly updated information is available on the website of the Federal Ministry of Health: www.bundesgesundheitsministerium.de/coronavirus. There you will also find, in particular, links to the information provided by the Federal Center for Health Education and the Robert Koch Institute.