Good luck!
I don’t do German but I do Spanish (my exams on May 3rd), and I know that for the general convo, it should be between a x-y minutes. You should’ve already been told this? Also, try to time yourself overall with how long it’ll take. Try to shorten some answers as a minute per answer is quite long. Even if it’s short you can easily include answers that use different time frames and spontaneous vocab etc.