In your EHS box, find the small EHS36 box, the short, rounded cord (RJ12) and flat cord with thicker ends (RJ45). You can pack the rest of the box back up
Plug the large jack of that end into the AUX port, and the small into the green TEL port on the Leitner
Unplug the power cord from your Leitner base
Connect the longer, flat connector cord into the left side of the EHS box. Plug the other end into the AUX port on your charging base
Connect the short, round connector cord into the right side of the EHS box. Plug the other end into the "EHS" jack on your telephone
Plug your green telephone cable into the green telephone port on your charging base and plug the other end into the headset jack on your telephone
On the underside of your charging base, set the two switches to "1" and "DHSG"