Within Rhino there are built in tutorials with PDFs and template files that can help you get started, 

These are available to all users in the newer versions of Rhino

To access these simply open Rhino and type the command 'Tutorials'

From here you have Level 1, Level 2, Sample Models and User's Guides

Level 1 and 2 take you through a number of tools on how to use Rhino. This can either be a way to learn all the tools or if someone mentions a tool you are unfamiliar with, this can show you what it's capable of.

Sample Model is a small library of models created inside of Rhino. You can use these models to see what's capable with Rhino or simply to play with them, break them apart or practice tools like rendering. 

The user guide again is self explanatory, this is more a general overview of Rhino compared to specific tools and for a complete beginner is a great place to start.