It displays a thumbnail sized version of your canvas, and allows you to zoom and pan.
The Navigator will serve as your roadmap. It displays a thumbnail sized version of your canvas, and allows you to zoom and pan. The small and large mountain buttons control the zoom, and the red rectangle can be dragged around to pan your canvas when zoomed in. You can position these palettes wherever you like, but I like to keep them on the left side of my window. This layout works well for me because I am right handed.