Run through lessons 1-4 for an introduction, and 5-8 for advanced lessons. Lesson 8 uses a tsch shell where as most everyone else uses bash and thus setting paths and environmental variables is slightly different.
You'll need access to a shell application. Find a Mac, and launch the Terminal application under the /Applications/Utilites folder. Windows users can login to a linux machine using puTTY but this requires an account and is more bother than simply finding a Mac.