Like so many things technical, there are different approach options you can take
- The cheapest, easiest, lowest resolution is to use Canon's software and use USB, ... But that camera (its what I have) is USB2.0 so video resolution will be low with this approach
Assuming your computer is powerful enough for real-time video encoding, and has a free USB3 port
- the much higher video resolution approach is to use HDMI out of the camera, get a USB HDMI capture device (beware cheap devices with poor drivers/support) and set that up. Get video input working at Operating System level first.
Once video input working at Operating System level, you should then be able to add the camera as a Video Source in OBS
There is a getting started guide on this site. Paul Richards also a free ebook (PDF) and using OBS Studio that is not gamer oriented, and might be a good place to get a more thorough understanding of OBS Studio