Video editor for gaming

I want to start making YouTube videos about video games. I have a device that records footage between my console and the TV and saves it on a USB/SD card so I can record the gameplay. And I have a camera setup pointed at me with a microphone so I can record myself playing the game, which is also saved to a USB/SD card.

With these videos files, what is a good (or best) video editor that will let me place one video in the corner of another like a typical streamer would have on Twitch.
I don't have very much experience editing videos so I don't even know if this is a standard feature of video editors now days. In which case can someone then tell me what is the simplest video editor to use instead.

I would prefer something free but I am also willing to pay if it is simple and does what I want.

Thanks for any help.

Try Lightworks, OpenShot, Shotcut and iMovie (only for macOS). All these are free.

You can use Adobe Premiere Pro, AVS video editor and blender, shotcut and lightworks. All are free except Adobe Premiere pro.

I think Filmora would be a good bet. They have pre-installed transitions/effects and it's pretty easy to learn. It is a paid software, but the free trial is full-featured (exports with watermark).

sony vegas pro is the most simplest video editor in my opinion.