The first worksheet contains all the column and test metadata (column names, test types, operators etc.) that is normally present in the GUI. This metadata is visible as dropdown menus when you click on a column.
For example, the
Function
column will show a drop down of all the Test types (e.g. Count, Value, Outer Value etc.) which are available. The Field_A (and Field_B) columns will show drop downs of the corresponding columns for Table A and Table B in the Table Pair etc.
This information speeds test creation in the spreadsheet, helps reduce input errors and eliminates the need to memorize items (like Test types) or specific column names/types etc.