1. Following the Installation Instructions

2. Run the PHP built-in web server. Supply the -t option to point to this directory:

   $ php -S localhost:8000 -t examples/
   

3. Point your browser to the host and port you specified, i.e http://localhost:8000.

G Suite APIs such as Slides, Sheets, and Drive use 3-legged OAuth authentification. Samples using OAuth can be found here:

https://github.com/gsuitedevs/php-samples