How to download streamed video?

I use the open-source program OBS Studio.

Can you please give me some guidance how to use this? I have minimal understanding of video streaming

Here's an article on it (scroll down or search for Open Broadcaster Software):
https://www.howtogeek.com/183231/how-to-record-your-desktop-and-create-a-screencast-on-windows/

Here's a pretty good YouTube video on it:
https://www.youtube.com/watch?v=r7teWxV5BCE

I watched a couple tutorials. I am having a problem getting the window of the browser to appear in the OBS viewer. The stream I am trying to record is a box within a internet explorer browser window. Can you please give me some guidance here?

A bit tied up today, but will try to put together a step-by-step guide later tonight ...

You are the best! Thank you so much Sam!

I'm trying to use OBS to record my IE11 window, but I'm just getting a blank screen.
Seems like others have the same issue.
I use Firefox and can record without any issues.
Do you need to use IE, or can you also use Firefox?

Firefox will work fine.
Is there any advantage using OBS over Camtasia?

Firefox doesnt work either

I am naive to streaming. I thought that maybe there was a way to capture the video file as it came in, rather than do a screen capture. I will stick with Camtasia. Interesting, the audio did not record properly using IE, but worked fine with Chrome.

Thank you!!