When starting Blender, the splash screen will appear in the center of the program window. This screen will allow you to create new projects or open recent projects you've recently worked on.

You can close the splash screen by clicking anywhere outside the splash screen (but inside of the Blender program window) or by pressing the Esc key.

You can reopen the splash screen by clicking on the Blender icon in the Topbar and choosing Splash Screen.