Need help getting my game aspect ratio to match my camera preview

So I am making a Pong clone (more like wall ball, aka one player no AI Pong) for practice (i.e. no tutorial) and I have this for my scene and camera preview:

But when I test play it, the screen looks like this:

I think I'm supposed to go into the build settings and then to player settings to find the resolution and presentation settings, but how do I get rid of that extra black space? Changing the fullscreen aspect ratio or windowed screen size result in my game looking about the right size, but with half the game cut off because it's not centered. I centered it in my scene so I'm not sure why that's happening... Can anyone help? I'm not quite sure what to even google to find answers, which I usually try first when I hit a question/problem.