Here's Google's training info on Google Docs & Drive 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.
Google Drive (sometimes called G-Drive) is where you can store files online. It's like having a file cabinet that you can get to from any Internet-capable device.
Google Docs is an application within Drive that allows you to create, share, and collaborate on files that are then stored in Drive.
Docs auto-saves your work every few seconds, so there is no save button - don't freak out!
You can view Google's list of keyboard shortcuts for Docs here.