Keep in mind that your main means of transportation is a bicycle, so dress appropriately for the bike. Please pick up your application materials from the Office of International Education. They are in suite 140. It's to the left when you walk in the building from the front. You are on your own.
Most students fly to a European airport then take the train to Oldenburg.
Here are some airports in Europe, listed according to proximity from Oldenburg. Other routes are possible, too, such as through London or Brussels. Bremen is by far the most convenient. You can get directly from the Bremen airport to the train station via the street car. Hamburg is also good, but you still have to change trains in Bremen to get to Oldenburg.