Your question doesn't have much detail, so it's tough to say for sure what you're looking for. I'm going to assume you are running a heli with the Vortex FBL and an R3 running UDI since Spartan said you need a REX receiver to run EX bus with the Vortex.
If that's the case, and you have lights with a controller, just plug the controller into port 1 or 2 on your R3. Then in your Jeti, setup a channel for the lights (let's say channel 8 for this discussion) and map it to a switch. Now go into Device Explorer, Receiver Outputs, and change the value of the port you plugged your lights into so it is sending out Channel 8 for your lights.
That's it. Easy.