The Validate Error alert uses the Conditions column to evaluate if the user input is erroneous and the Description column to serve as the error message. Both of these fields are found in the Action grid.
To create a Validate Error action for a workflow:
In the Alerts grid, select the workflow row (event) to which you want to add the action.
In the Actions grid, click Insert and select Validate Error.
Complete the field in the Alerts grid.
Click Save.
Create a Validate Warning Action for a Workflow