Please see the Programme Booklet for directions.
Düsseldorf-Airport to Bielefeld is about 1h30min by train. The train station is at the east side of the airport grounds. You can get there directly from the terminal by taking the SkyTrain.
You can buy your train ticket online but you can also buy it in the train or at the train station using a credit card. In addition, you can purchase your ticket at a counter, which usually takes you some waiting time.
For further information and timetables, please consult the Travel Service of the "Deutsche Bahn"
Frankfurt-Airport to Bielefeld is about 3h30min by train, most likely with one change of trains. Depending on your connection, this change is in Köln (Cologne), Dortmund, Düsseldorf or Hannover.
Note that, at Frankfurt-Airport, there are two train stations. Do not use "Regionalbahnhof", which is for regional trains, but go to "Fernbahnhof" which is for long-distance trains.
You can buy your train ticket online but you can also buy it in the train or at the train station using a credit card. In addition, you can purchase your ticket at a counter, which usually takes you some waiting time.