How well any meeting with a German bureaucrat goes is directly related to the documents you’ve managed to obtain. Always take every required document or risk being told to return with your paperwork in order. At the same time, don’t let a government employee tell you a certain type of certificate is required if it isn’t listed in their own publications – be insistent if you’re positive that you’re right. Translations are rarely necessary but, if required, must be done by a government-recognised translator.