If nothing was unclear or difficult, say so. Skip questions about steps you did not experience; use not applicable where appropriate.

How did you submit a question?
What prevented your question being considered?
What explanation would help?

Author notes / illustrative keys where applicable:
1. Use this answer to locate the part of the experience that needs explanation. The example issue to investigate is: attendees do not know how questions are selected.
2. The barrier helps distinguish submission access, selection rules and timing constraints in audience questions. Explain the actual route and limits; a question not discussed does not necessarily indicate that organizers ignored it.
3. Turn the requested improvement into a testable next step. One illustrative action is: explain submission and moderation criteria.