For travelers entering Germany from a SARS-CoV-2 risk area after a stay of several days, a 14-day mandatory quarantine and the obligation to undergo a corona test apply.
Immediately after entering the country, the persons entering the country must "go directly to their apartment [...]". Upon arrival at the place of domestic quarantine, you are also obliged to report to the local health authority. Further information can be found on the website of the Federal Ministry of the Interior.
During the 14-day quarantine you are not allowed to leave your home, not even for a short time and not even to go shopping. You are also not allowed to receive visitors during this time. Please clarify with your scientific supervisors, colleagues, friends or landlord how your care during the quarantine can best be organized.
You can do the corona test (PCR test) before you enter Germany - it must not be older than 48 hours at the time of entry and must be available in German or English. Germany accepts tests made in other EU countries and from some third countries. A list of these countries can be found here.
You can also take the test up to 72 hours after your arrival in Germany. We recommend the test centers at the major German airports, e.g. in Frankfurt, Berlin or Munich or at Berlin Central Station. The tests are currently free of charge for people entering Germany from SARS-CoV-2 risk areas.