Here's Google's training info on Google Calendar Level 1: The Basics and Classroom Application (Level 2). They're easy-to-follow and quite nicely laid out. If you're feeling ambitious, here's the Advanced info.
Calendar is your scheduling system moved onto the Internet. Because it's all stored online, you can access it from any Internet-connected computer. And because it's a Google product, once you're logged in to your Chrome account, you will automatically sign in to Calendar when you visit their web site (calendar.google.com) within Chrome; if you're not signed in already, you will be asked to sign in to the Holmdel GAFE domain.