Thank you for sharing your situation with the Wefugee Community!
Please find the requirements for getting the German citizenship here or here (though some points listed on that website may apply for applicants in Berlin only, i.e. "erster Wohnsitz in Berlin").
You may also want to check this thread, in which Isa already explained the details very well.
However, holding a residence permit for three years might only be sufficient, if you are married to a German citizen.
I hope this helps and please get back to us with any further questions.
All the best,