Opening: choosing what to explore
The question Explorer opens with: which entities, and which of their records.
The opening steps
Opening: Explorer opens by asking what you want to explore. Choose the entities on the left into the box on the right; the entities related to the ones you chose are tinted, nearer the darker, and listed first. Each large entity then asks which of its records you want, starting from what you chose for the one before where the two have the same kind of field. The steps are shown along the top of every page — the ones done, the one you are on, the ones to come — and Back returns to the step before with what you chose there. Open the usual columns skips it.
Later
Add column opens a new column at any time; Change source in a column's menu reads another entity in that column. A large entity asks which of its records you want then too.