The Hymnary stores two types of records: instances and authorities. An instance is essentially a page in a particular hymnal. An authority is the master listing of a text or a tune.
This structure of instances and authorities makes the Hymnary powerful for users, but complicated for editors.
The most important thing to keep in mind if you are entering or editing data for the Hymnary is that instances should show exactly what is on the printed page—even if it's incorrect—and authorities should contain only global information about a text or a tune such as author, meter, and incipit. If you keep in mind the fundamental difference between instances and authorities, the rest of the details will be much easier to understand.