What Do You Mean German Universities Don't Have Orientations? Even For International Students?
When you start at a Germany University, there are a lot of notable differences, from a total lack of a "traditional" campus, to oddities in exam registration, to the total lack of orientation courses for new students. Even for international students, exchange students, and, yes, brand new German university students. What are you to do?
First and foremost, look into the particular university that you will be studying at, either for a semester or two, or for your full degree. Some universities may offer language courses prior to the start of the semester which will run for a few weeks. This is likely the closest to a true "orientation" type program that you will find, and will give you enough time to get settled in the city and register for your courses alongside the full time students during the normal registration period.
Regardless of the availability of a language course at your university, there is always a student office, an international office, and either program or faculty office available to you. The international office is the best place to start, as they can help you with your various registrations and paperwork, as well as setting up visa and other appointments (if you ask nicely, of course).
As a student studying abroad, particularly if you are doing so through a program offered through your home university or college, you may have a contact person in the student or international office that you are expected to go to directly. If you don't, and you can't find other information, look or ask for the office that the ERASMUS (a study abroad program for European students specifically) students are expected to go to.
If you can afford to or your home institution has some way to help you pay for it, a program like a language course offered through the Goethe Institut may be an option as a low stakes way to get used to life in Germany and practice your conversational German before starting the semester. There are courses offered all over the country, and housing may be available (for a cost) at the location of the course center. That being said, if you do choose to take part in one of these courses outside of the university that you will study at, be aware that you will have to sort out all of your various registrations in a bit more than a hurry once you arrive in your final city.
Lest you think that you're totally on your own for learning about the city you'll be in, you're not! Typically, the Studentenwerk (student office), international office, or a university run international student club will organize tours of your local city, events for international students, or even tours of neighboring cities. Ask at the international office of your particular university about what is offered, and go join!