The first official step, if you have not already done so and are already in Germany, is to register your address („Anmeldung“). If you have been in Germany for some time, you will have already done some or most of the things described here. However, make sure you don’t leave anything out so that you avoid unnecessary difficulties later.

If you are staying in Germany for longer than 3 months, you will need to register at your local „Bürgeramt“. To do this, simply look up the contact on the Internet.

The law requires you to register within 14 days of moving to Germany. The so-called „Meldepflicht“ stipulates that everyone, whether German or foreigner, must register at their home address. The registration authorities register people to keep track of the population and where they live.
Mostly the authorities do not see this deadline as too tight, but you should stick to it if possible.

As long as you don’t have a permanent address in Germany, registration can be tricky, as one of the documents needed for this is a housing provider confirmation signed by your landlord.
In a few communities, it is possible to have this issued by the landlord of your temporary housing, but usually, you cannot register until you have a permanent lease.