On your screenshot I see the Sort Fields property between "Maximum Row Count" and "Child View Sort Fields" properties.
This is what the doc says:
This property defines the initial sorting criterion for the data. This is the syntax for this
FieldName1 [SortDirection], FieldName1 [SortDirection]
SortDirection is either ASC (ascending order) or DESC (descending order). Please note
that the FieldName and the SortDirection are case sensitive. If the SortDirection is not
specified, ascending order is assumed. For example:
First Name ASC, Last Name DESC, Company