I understand that, but there's not really much else you can do is there. It sounds like it's the latter stages of the process anyway, so upload the docs and cross your fingers.
You need paperwork from the place you’re going to be using. It already needs to have been paid for and they have to send you specific documents for your DTV application. It can’t just be a general interest you have in unspecified activities.
You need to have chosen what the activity is before you apply for the visa