"Information about the map and the panoramas"
You can click in an empty area of this map to search for the nearest spherical panorama in a certain radius of 150meters. If after the click, a panorama is found then it will appear in the window on the left plus a respective Pin icon
and a Google Street view icon
will appear in the central map too
You can drag the Google Street View icon
to a new position or click in a new area to search another panorama.
Finally by pressing the recenter icon
you can recenter the main map to the selected Google street panorama.