To create the same video in different dimensions, follow these steps:
Step 1: Make sure the template you have chosen is available in more than 1 dimension.
Step 2: Export the video that you are creating.
Step 3: On the 'My Projects' screen, select the exported video.
Step 4: Click 'Duplicate'.
Step 5: Choose the new dimension and click 'Duplicate Now'.
Step 6: Go through each scene and make sure everything is fit according to the new dimension. Check out new scene styles in 'More Scene Options'.
Here is a detailed tutorial on how to create the same video in different dimensions: