You're tagging your paper against four facets. Selections happen at the sub-pile level (the second-level names), with a fallback to whole-pile tags if no sub-pile fits.
Tips:
Pick two of your own published papers — ideally spanning different areas — and tag each across Domain / Method / Users / Primary Contribution.
Important framing: you are not tagging "what is this paper about?" You are tagging "what expertise should my reviewer have to do a good job reviewing this work?" Hold that question in mind throughout. We want to know whether this reframing lands, or whether you instinctively default back to topic-tagging.
While tagging, please notice — as the author:
Then capture everything in the feedback form linked in the email.
Time budget: ~7 minutes total (≈3 min per paper). Don't be exhaustive.