Set up multiple screens

Do you perhaps mean "Spaces" rather than screens? If so, you can swipe up with 3 fingers on a track pad to open Mission Control and see your Windows and spaces. Spaces will be at the top. You can add a new space by clicking on the + sign.

If so, see the following support document to manage desktop spaces.

click here ➜ Work in multiple spaces on Mac - Apple Support

click here ➜ See open windows and spaces in Mission Control on Mac - Apple Support

Check System Settings>Mission Control...

Sorry your question is not very clear.

Are you saying you have 4 connected external monitors to your Mac you can't find?

An M3 iMac only supports 1 external display in addition to its own display for a total of 2 displays.

You can manage those displays in System Settings ➜ Displays.

You cannot use anymore than that.

click here ➜ iMac - Technical Specifications - Apple

and here ➜ Connect one or more external displays with your Mac - Apple Support

so the desktop spaces was not what you meant?

You keep using the word "screens", but I don't think you actually mean screens.

Perhaps you mean App windows.

Maybe you are referring to windows for apps you have opened?

Perhaps if you take a screen shot of what you mean if would be clearer.

How did you use to scroll through these "screens" before? What exactly did you do for that?

Maybe if we understand what you did, we can then know what you are referring to.

As it stands, I have no idea what you may be referring to.

Perhaps you should seek help in your native language. either your explanation of the problem isn’t coming across clearly or the answer isn’t translating well enough for you to understand.