Seems like we need a little more information.
Sounds like you are trying to get a composite baseband (Yellow RCA) to show up on a TV but the TV does not have an RCA composite input (of course, if it does, just plug it in to the TV and change the TV input to AV-1 or whatever the input says on it)...
If you Dish receiver is hooked up to the TV via the coax, and you have your TV on channel 3 or 4, then you can use the modulator. Set the modulator to channel 65. Use a two way splitter to combine the Dish and modulator signals.
(Wire from Dish box ANT-out - it might say to TV) to one "output" of splitter. Modulator output to other "Output" of splitter. Then connect a wire from the splitter "input" to the Antenna in on your TV.
Make sure your TV is set to CABLE channels not antenna - then you chould be able to go to channel 3 (or 4) to see the dish box and channel 65 to see the camera.
Unless I misunderstood the whole thing that is.