You have to manually do that, Windows Snap currently does not support that layout.
You can press Windows key + up, down, right or left arrows to manipulate how the windows appear on screen.
If you would like to see this improved, please send in your comments and suggestions using the Feedback Hub:
https://windows10.help/blogs/entry/54-how-to-su...
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.