Start with three questions someone actually asked
For a new flat, the first entries might be “Where are the spare bulbs?”, “How do we book the laundry room?” and “Who has the parcel key?” Ask a second person to find one answer. Their search words make better labels than a formal filing scheme. Use the answer people need first as the entry title. “Spare light bulbs” is usually easier to scan than a grand section called “Domestic resources.”
Make each answer usable on its own
A good first entry gives the item or task, its location or owner, and a way to check it. For the parcel key, record who holds it and when that was confirmed. Leave access codes out. A handbook should help the reader reach the right person without creating a second store of sensitive credentials.
Test and expand the index
Ask a partner to find one answer using only the index. If they look under “lights” rather than “supplies,” add the familiar term or rename the entry. Keep an empty topic out until there is an answer worth maintaining. The reader's failed search is a better reason to add an entry than a desire to fill a template.