Calculate expression for external program execution

I’m trying to build and pass parameters to an external program (bat file). However, when attempting to specify calculated arguments, none of the columns of the table appear in the expression builder. Shouldn’t I be able to select column data to pass as a parameter?

Column names aren’t available in the “Run program” action because it runs another application once but a column can have multiple values, so it creates ambiguity.

Instead, you can use the “Iterate program” action that can calculate command-line arguments using an expression with column names and will run the external application once per each row in the table.