Rotate Camera with Mouse Movement

I already have that checked off. The problem is that when I start the game, the cursor doesn’t control the camera unless I have a mouse button held down.

I want the cursor to control the camera without having to click or do anything. I know it’s gonna be something simple and stupid which is usually the case since with me in coding so far, but I just can’t figure out what to do. And none of the tutorials I watched are giving the result that I want specifically.