On the Fields page you have to set the pairing of the source and target fields
by setting the source field name and the target entry name.

With the plus button you can add fields one by one.
With the refreshing button you can get all the fields from the source dataset on this page.Each column of the SQL statement can be assigned to an entry of the target object.
In other words, each row returned by the SQL statement results in a new dataset in
the target object and it is determined where the entries and the columns are written.
So we need some kind of one-to-one correspondence between columns of the SELECT statement
and the entries of the target object. This correspondence is typically achieved either by a
proper SQL statement which gathers, groups, and combines all necessary information in the
desired form, or by some temporary fields in the target object which can serve as a basis
for further calculations.
Note: If a field from the list does not exist in the source dataset, then its
background will become red .