adjusting camera in key frames

Im doing a youtube lesson on blender. I started a few days ago so Im very new. In the lesson we built a cube with a sphere on top and used the Camera to go aroudn the object so it would do 360 degrees so you could see the entire thing. In key frames we were editing where we put the cameras.(If they needed to be higher/lower, moved to the left or right) to make the 360 more smooth, less jerky.

At about 4:00mins in the video. all of my cameras are selected not just one so I cant adjust…How do I fix this?