Did you add the time dimension to the Data Source View then add the foreign key relationships between the fact tables and time dimension? Then you add the time dimension to the cube.
The article was written based on creating a cube without a data
source. In order to add time intelligence to an existing cube, you
open the project, select the cube, click the Cube menu, then select Add
Business Intelligence which will launch the Business Intelligence
Wizard. Select Define Time Intelligence and complete the wizard.
It would probably be worth following the steps in the article and setting up the time intelligence in a test cube to get familiar with all of the settings.