First, you need to select a layout. Click the DDM icon in your system tray to open Quick Settings, then look for the Easy Arrange icon. Press '>' or use the Page Up/Page Down keys to browse through the pre-defined display layouts. Once you find one you like, simply drag your application windows into the defined zones.
If Windows Snap is interfering, you can give it priority. In the Easy Arrange settings, select "Hold down the SHIFT key to enable zone positioning." After that, you'll need to hold the Shift key while dragging to use Easy Arrange positioning.
If that didn't work: The application you're trying to snap might require a minimum window resolution. If the Easy Arrange zone is smaller than that, the app won't fit. Try a layout with larger zones.
Heads up: You can create up to 5 custom layouts. Just arrange your windows how you want, then click 'Save' and name it. Press Ctrl+Shift+Home to cycle between your 5 most recently used (MRU) layouts.