On home page, tap title of the note that you'd like to open in split screen, then tap Open in split view.
On devices < Android 12L, you should first enable split screen mode by going into your devices' recent apps screen, then long hold Notewise to enter split screen mode. Now you may tap Open in split view inside Notewise, as shown in the image below.
Note that not all devices support split screen. If you're not able to find the Open in split view button, the mode might have been disabled by your manufacturer.
