When a variable (%K, %V, or %M tokens) is placed in the Expression field, the variable is listed in the Variables box.
You can select a variable to further specify the variable's value and data type by selecting the Variable has a value check box and defining the variable. Enter the value(s) into the field.
Select The value is an array (separated by commas) if the variable is an array.
Select the appropriate Data Type from the drop-down list. Click Set when the variable is configured appropriately.
You can add configured variables from the list to the Expression field by double-clicking on a variable in the Variables list. The variable is added to the cursor's location in the Expression field. If text is selected in the Expressions field, that text will be replaced by the variable.