Enable keystroke navigation for switching between open desktop browser windows using Command (or Cmd) ⌘ + ~ (for Apple keyboard).
This already works. If it is not working for you you might need to check keyboard shortcuts on your OS.
I figured out the issue. I had the windows set to Full Screen, and one of the two was minimized. Once I maximized it and turned off Full Screen, I could toggle between the two. Thanks for the input!