If you just plug the other elevator servo into Ch 8 and turn it on that's the automatic default for two elevator servos. Then just plug the battery into ch 5. The RX doesn't care what open box you plug the battery into.
It's in the 9-C instruction book, you don't even have to go on line to figure it out.
If you have A problem hit me with an email and I will walk you through it. My TX is out in the shop so I have to work from memory right now.
Sure, like that would work!!!