Set unique format for a project

I have a digital sign for which I need to create vids that have an aspect ration of 800 X 240. I cannot figure out how to create a project with that aspect ratio. See attached video. In another vid progran I use, no matter the project template, when I import a vid, it would ask if I want to set the project to that ratio. I then choose yes or no depending on the project.

I have found there is no way to alter an aspect ration of any of the template designs. Also I am not asked to match a vid aspect ration upon import.

Is there a way I can create my own video template design?