When you choose this action for a validation rule, an information string is attached to a specific field. The string is then available when you type both conditions and actions for other validation rules. Add .Info to a field name to access its information string. (This string is called TemporaryStorageString1 in FORMS' API.)
Specify a name for the action. This is just a label to help you remember what the action does.
Specify which field is to have an information string added to it.
Create the information string. Either type an expression yourself, or click Expression, which opens a dialog that can help you write the expression. The result of the expression must be a string or a numerical value. (If you want to write a simple text message, enclose it in quotation marks.)
Click OK.