This example displays a custom panorama of the Google Sydney office. Note that this example doesn't use a map or default Street View imagery.
Read the documentation.
Git and Node.js are required to run this sample locally. Follow these instructions to install Node.js and NPM. The following commands clone, install dependencies and start the sample application.
git clone -b sample-streetview-custom-simple https://github.com/googlemaps/js-samples.git
Other samples can be tried by switching to any branch beginning with
git checkout sample-SAMPLE_NAME