Going to YouTube

I'm certainly no expert on editing. There is one simple program that allows you to easily clip out sections of a video called "Vidcutter." You can download it free for pretty much all platforms, and you can also get it in a single package in which you just run one file and it already contains "everything" you need to run. Called "appimage"

It can be a bit glitchy but it is easy

VidCutter

If you are unaware you can downsize files to YouTube as you upload it--the YouTube software will do that "online" so to say