Gotcha.
Next up is power to the receiver.
It's been a few years but as I recall, the KK2 powers the receiver through the 5v rail on the throttle receiver port.
The KK2 gets its power from a BEC on one of the ESCs through the 5v rail on the motor ports.
So, to power the receiver, you have to power the KK2 with 5v.
I assume your ESCs have BECs to send 5v to the KK2.
If so, connect your receiver throttle channel to the KK2 throttle channel (mind the polarity) and an ESC to your KK2.
THIS NEXT STEP WILL POWER YOUR BOARD SO BE SURE YOUR PROPS ARE OFF!
Lastly, connect power to your ESC.
11.1V should go through your ESC's BEC, into the KK2 and power your receiver. I am hoping a little light turns on when you do this...