Rhino’s interface consists of a menu bar, a command window, toolbars and sidebars, panels, viewports, and an object snap (osnap) toolbar. Each of these interface components allows you to communicate information with Rhino in different ways. Usually, the Command prompt includes information about what Rhino expects you to do next – it’s good practice to check the Command prompt for instructions.
See this link for more information on the Rhino interface.
Viewports are windows through which your model is made simultaneously visible from different vantage points and in different projections. There are four viewports by default.
Double-clicking a viewport title will toggle between a full-screen and a tiled view.
Useful viewport-related commands:
PANNING, ROTATING, AND ZOOMING.
Hold down the right mouse button to rotate/orbit the view within a viewport.
To pan the view, hold down SHIFT while holding the right mouse button.
Roll the mouse wheel to zoom in and out.
See this link for more information on navigating in Rhino.