OpenDA is Open Source: it is developed, extended and supported by its users. The OpenDA association stimulates the further development of a user community through its forum and by organising user meetings. So, your professional peers are probably the first place you go to if you need help. Please, search the forum on sourceforge or The OpenDA Group on Linkedin first because chances are that your problem was encountered and solved before. If the OpenDA software behaves different from what you expect, you could take a look at the bug-tracker (at Sourceforge, not yet operational) to see if your problem has been reported before. If all this fails, you can drop a message on the forum or Linkedin and hope that someone will answer it. The user community has been relatively small so far, so we don't know whether it will support a growing user group. But it's worth the try.
Course material is available on this website under Documentation/OpenDA course. That is simply the material that was used in previous courses. It gives you the slides, but obviously not the talk that goes with it. So, perhaps it is not enough for you.
The OpenDA association offers support packages for professional support, please check out the different options in our leaflet OpenDA_support.pdf.
If you require professional support that is not offered by the OpenDA association, you may also check out the Partners page. There you will find a list of OpenDA partners that can supply you with different kinds of services on a professional/commercial basis. Partners are usually also in for cooperating with you in offerings to third parties.