To power your gimbal you will need to connect it directly to your battery power (I am assuing you are using a 3S battery?) The power connectors are the two largre red 
and black 
on the left of the gimbal controller board used in the images above. Usually I would just solder a connect the gimbal controller directly to the power distribution board. However if you are using a larger voltage battery that is beyond the voltage range of your gimbal controller board you might need to use a voltage regulator between the gimbal controller and your flight battery.
You dont need to provide any power along the pitch control, as it is powered from the main power of the gimbal controller. Just connect the PWM signal pin, and the ground to any spare output on your CC3D.
As I said it depends on which CC3D version you have to enable the RTH features as you will need to have a pressure sensor and compass sensor, but if you dont have these then I guess you dont have the CC3D revolution board, so you will not be able to use these features for now. Most of the cheaper CC3D boards you can buy off ebay dont include any pressure sensor as its not needed for miniquads.