Splitting your screen is a useful way to take class and have your notes available for reference without having to switch between different tabs or manage overlapping windows.
Depending on the version of macOS you’re using, the interface for this feature is slightly different. For more information, see the support.apple.com article: Use two Mac apps side by side in Split View
On Windows 10 you can use the snapping mechanism to split your screen between Forum and another application.
To split your screen, open Forum in a window, and your notes in a separate window. Then, drag your preferred window to the edge of your screen and let go: it will snap into place. When you have snapped your desired window to the edge, you will have the option to select another window to fill the other half of your screen.
Click on your notes window and it automatically snaps into the free half of your screen.
To adjust the width of either window, click in the shared border of the windows in the middle and drag to the left or right.
The shortcut key to split the screen is Windows key + Left or Right arrow.