Select an activity that uses expressions, such as the assign, wait, or on alarm branch of a pick activity.

In the Properties view for the activity, select the appropriate property. For example, in an assign activity, select Copy Operations, and select Expression as a Copy/From type to display the following dialog:

Select the variables, functions and operators from the three boxes to build an expression, following these tips:

Build expressions faster with shortcuts. See Using Content Assist.
Expand a variable to see and use the parts and properties. For detailed descriptions of variables, see Using Variables.
Select a variable, part, function, or operator and select
Insert
For working with variable attachments, see Custom Functions for Manipulating Attachments.
Add your own custom functions, as described in Creating POJO and XQuery Custom Functions.

Select

Evaluate

to substitute a sample value for a variable part and simplify the expression to view its value.