Only Two Names Allowed, First and Last

Question:
Please, I wish to know how to sign according the law in Germany which allows only two names. Have a family name before [name removed], I use here. Or if only signature matters: [name removed]. I normally sign: [name removed]. On the Birth Certificate: [name removed]. It seems only [name removed] is Ok. The question: I do not know how to balance. WHAT IS NAME IS BEST? The problem: 25 years of university (as student and later work in parallel) and financial life too much up and too much down last 20 years almost down and dependable. A B.A.( four years) in English/German Language Literature; Clinical Psychology M.A. and Psychoanalysis (Training: 10 years): Ph.D. in Electrical Engineering: would like to improve my financial life. As Psychoanalyst I got sometimes a situation but do not stable. Lived in 4 continents, included countries like CANADA and FRANCE ( by myself) and in others by UN due marriage and now I have to do an action urgent in order to accomplish my ideas, theories, goals and of course, a stable financial life. It was almost. Ok...but I should settle down. My vocation is Choreographer and/or Authentic Movement Therapy. My profession is Psychoanalyst but I think it could be great to be near my vocation. Wish balance focusing Financial Life. It is a real catastrophe now. Thank you for your read, time and consideration.

Answer: (Responses to questions rely on the accuracy of the name and birth date provided with the question. Typographical errors or incomplete information can result in an incorrect response.)