The Spreadsheet model is broken into Template Model Areas based on a Business Process, Sub Business Process or Task.
By expanding the folder on the Spreadsheet Model tab, you can view the fields in each Template Model Area. You can edit those fields by clicking on the Edit Template Model Area button.
Whenever you are
prompted for a value for a field while populating an action or task online, you
will have to specify a Reference ID Type. This is a "lookup" field
that must be populated with a valid Reference ID Value in the integration file.