Now that you’ve arranged your monitors on your desk, plugged them in, and turned them on, it’s time to consider the software side of things. This is how you create a consistent experience between displays. You want your mouse cursor to flow naturally from one display to the other, and in the sequence in which they are arranged.
With your external display(s) connected, launch System Preferences > Displays. On your primary display (i.e., your MacBook or iMac screen), click the “Arrangement” tab. All detected displays are visible on the diagram. Click and hold on a display to show a red outline on the corresponding monitor. Uncheck “Mirror Displays” if you see the same image on both.
Now, click and drag your monitors to arrange them in the same order in which they sit on your desk. You can drag a monitor to any side of the screen, including above and below. Pay attention to the offset between the monitors, as this affects the point at which your cursor moves from one display to the other. Play around with the arrangement until you are happy.
