OneNote is a great tool, and I can hardly function without it now. But there are times when I need to have the OneNote page displayed side-by-side with the other application I have on the screen, and I don’t want to keep switching back and forth between screens. I can do that by automatically docking my page to the side of my desktop.
When you have a new (or existing page open, go to the View > Dock to Desktop icon in the Ribbon Bar:
When you click that icon, the open OneNote page will dock itself to the right side of the page, and your other open windows won’t use that docked space:
And if you need to get back to having your OneNote screen float around like normal, you can click the two-headed arrow in the upper right corner of the docked page: