Where to find RSSI?

Hope I got the correct category. First post. When using the Cube, an X8R, and a Taranis, how and where do I turn on the quadcopters battery voltage so I can see it on the ground? Where do I find it on the Taranis during flight? No, I haven’t plugged anything into the “RSSI” port on the copter but am using the sbus port connected to RC In.
Thanks

Your answer is below. You’ll need to roll up your sleeves a bit.

http://ardupilot.org/copter/docs/common-frsky-telemetry.html