Apparantly, either because I am using a secondary data source, or because the repeating section is contained in an optional section, step 14 in that link does not applay, as there is no "[Filter Data...]" button so I can set the position() function.
(I'm guessing it's because I'm linked to a secondary datasource.)
I am looking for help either how to select a single record when using a secondary datasource, or how to implement the Position() function for a repeating section contained within an optional section.
Also, step 15 of that link references the query using the data connecion: Main Connection. How will that work with the data coming from a secondary data source?