The screen modes button allows you to change what you see around your workspace.

Presentation mode locks the workspace and makes it full screen

Normal mode is the mode we have been using so far (it is the one I default to)

Full screen with menu bar pulls AI to the front of your desktop, think of this like focus mode. It is great if you are using only AI and not importing anything.

Full screen mode allows the workspace to take over the screen. If you know all of your hotkeys this may work ok. You can also hover at either edge to get menus to appear. Hit ESC to go back to normal mode.