Note: please use the web client to finish the steps below:
1. Go to menu Time Period Management > Configuration > Time Period Categories.
2. Search for categories with Type=Maintenance Window
3. Click Edit button under Usage Condition.
4. In Condition Editor pop-up, you can select RAD expression at first drop down list.
5. Enter your RAD condition as below example:
6. OK > Save and test to create new Time period again to verify result.