How TVs work: on each TV, open once in its web browser and set it as the home page. That address never changes: whatever you choose here shows up on that TV within about 20 seconds. TVs check in every minute, so you can see which ones are online.
Add a TV
Give it a name your staff will recognize.
On the TV, open . A 6-digit code appears. If that TV already shows something (even from before you had an account), it keeps playing until you finish here. Leave blank to add the TV now and pair it later.