How to enlarge a video with multiple small clips

[salen_8080]

Hello,

I am making a short film with different clips in horizontal and vertical format. When I edit them and bring them together (1 video on top, 1 in the middle and 1 at the bottom) the size of the final video is very small. How do I fix this issue? Thank you for your help

[Bill Sprague]

I can't visualize what you are saying.  Can post a screen shot of what you are doing?

[Peru Bob]

The pixel sizes of the project will be the pixel sizes of the first item placed on the timeline.