Setting the default film/frame size

1. Mouse over to the top menu bar.
2. Click 'File'
3. Click 'Set Film/Frame Size.'
4. Select the desired film size from the drop-down list.
5. Select the desired Aperture Name from the drop-down list (Aperture Names are a sub-category of Film Sizes).
6. Click the check box labeled 'Use the selected frame size for all new Projects.'
7. Click the [Apply] button when ready.