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

Which task brought you to the library?
What category label was confusing?
What filter 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: readers search by problem but content is grouped by campaign.
2. A confusing category reveals a mismatch between readers' task vocabulary and content grouping. Improve the label or provide a useful cross-link, while keeping personal navigation preferences separate from evidence about all readers.
3. Turn the requested improvement into a testable next step. One illustrative action is: add problem-based navigation labels.