This window lets you manually control the TV ON relay, to test that the relay is working and that it's properly controlling your TV.
Click the Relay On button to toggle the relay on and off. Use this to confirm that the relay is operating correctly. You should be able to hear the relay click each time you toggle it.
You can also click the Pulse button to simulate the brief on/off pulse that the firmware uses when you turn the system on. This turns the relay on for about a quarter of a second and then turns it back off. You should be able to hear the relay click on and then quickly off when you pulse it.
If you've wired your TV's on/off button to the relay, the TV should switch on or off each time you pulse the relay, since the TV should think you're pushing the button each time the relay fires.
If you're using the expansion boards, note that the relay runs on power from the secondary power supply (the one that's meant to power your feedback devices, marked "PSU2" on the expansion boards). So the relay won't actually turn on if the PSU2 power is off. It's designed that way out of a general preference in the expansion board design for keeping everything mechanical (like the relay) away from your primary PC power supply, since mechanical things tend to generate electrical noise.