Click the Additional Variable icon
or select Insert > Expressions, Functions and Variables > Additional Variable.The Insert Additional Variable dialog box appears.
Set Name to a unique name for the new Additional Variable. For details, see Valid Syntax for Named Objects.
Click .
The Additional Variable details view opens on the Basic Settings tab.
Specify the basic settings. For details, see Basic Settings Tab for Additional Variable Objects.
Click .
An object named after the Additional Variable is created and listed in the tree view under Expressions, Functions and Variables > Additional Variables.