This image shows the Variables and Functions tabs in the upper left. Variables is selected. Below Variables is the Sources section of elements. On the right side of the page it says CountStitchAssignment. Below that it says Data Stitch. Below that it says Count assign from 0. Below that it says book append from book. Below that are the Variable field (with a value of book), the Operation field (with a value of Append), and the Value field (with a value of $Trigger/ns1:execute/ns0:bookstore/ns0:book).