Welcome!
There is plenty of literature for freelancers in Germany on how to start a business, the first steps, etc.
I particularly recommend this book -- one of the best on the subject, for the most part available for free online! -- get a dictionary and work your way through it, and come back if you have questions.
----------> https://www.mediafon.net/ratgeber_einfuehrungstext.php3?si=56f053493921f&id =401017f4c01c0
I don't know how good your German is, but if you intend to freelance here you might as well start learning German using this book. Even if you plan to focus solely on English-speaking clients, you still have to pay taxes and get stuff done in the German bureaucracy and that will be much easier if you know the language. Mind you, they make life hard even for us native speakers
Lesezeichen