Probably want this in blue prints section not content creation.
Yes in your character pawn blueprint is where you would setup both the tank_base and the tank_Barrel and the camera boom and camera in the components section.
Then you probably want to setup a simple blend with the tank treads moving and turning IE the tanks actual movement forget about the turret at first.
Now you got a tank moving the way you intended with the tracks and what it sounds like you want is the turret to be tied to the camera and swivel based on camera direction.
I would look up the 3rd person to first person zoomable blueprint tutorial. During that tutorial there is a event in the defualt settings that you can turn on and off something like “Get Yaw”. Your going to bind or attach this function to the turret I would imagine and not the tank tracks below it. Also I came across this in testing this will allow you to be moving forward with the tank in one direction while looking with the turret in another.
Really I would gander at the section of the tutorial I mentioned above should fill in your blanks.