SEE: How to make a Landscape View or change the orientation of a View or Layer
You now need to to into "Edit View" for both your Landscape and Portrait views.
Click on the "Events" tab. And then click on pencil next to "Orientation Change" to bring up the Action.
Now use the Action "Switch to Another View" on each View. This way when you rotate the device it will switch views from landscape to portrait or visa versa.