From the CLA Polycom Video Conference System:
Make sure you are connected to the video meeting room and then connect your computer to the Polycom system using an HDMI cable.
From the CWJC Polycom Desktop for Windows:
This is already a computer so no physical connections need to be made.
Once you are in a session, click on the round icon with 3 dots in lower right:
Select the ‘Content’ icon in top right
You can then choose to share your desktop.