To Create a Valid Expression to associate with a Property Definition

Open the Expression Builder dialog (Item Types Dialog > Expression > Options button).

If you know the desired expression syntax, enter it in the text editor section of the dialog.

If you need help with building up the expression, do one of the following:

Expand the Select Function Group button.

or

Select the Show function group at current caret position button.

Select the desired function group.

Double-click on the desired function or property to add to the expression. This will then display in the text editor section on the right-hand side. At the bottom you will see a description for the selected function.

As you type in the syntax further, you will be prompted by a drop-down of options for functions and properties, double-click to add it to the syntax. For some Functions when selected, an additional section is available on the right-hand side of the dialog. See image below:

Select the desired details for fields in this section, which will get added to the expression's syntax in the text editor section.

Select any operators to add to the syntax from the Select Operators button.

Select Test button to check if the expression is valid. Based on success or failure of the expression, you will get a message displayed in the description section at the bottom.

If the expression is valid, select OK to add it to the expression field. If there is a failure you can select Clear and repeat steps (4) through (9).