Thank you for using OnSong! Here's how to display two chord charts side by side on an external monitor. You want to make sure you are in a set and follow the steps below:
1. Make sure you have HD Mirroring turned to Off. Go to the Utilities Menu (gear icon in the menu bar) --> Settings --> External Video --> Use HD Mirroring (OFF) --> Done.
2. Utilities Menu --> Settings --> External Video --> Stage Monitor --> Paper Orientation set to Portrait and Screen Orientation set to 0 or 180 --> Done.
Hope this helps!