Scanning technique to make modelling simpler

I’m new to this so bare with me

I’m trying to scan an automotive part so I can create a light pod that fits. When scanned it the first time, I didn’t get the back side and only captured the opening so when I started working with the mesh, I couldn’t figure out how to turn it into a body that I could model around.

Is there a technique I can use when scanning or when processing it (I’m using CrealityScan) before exporting it that will make it easier to work with or software (free ideally) that I should be using to prepare the part?

Thank you in advance!