Unless you already have an Android development environment set up you will need to use the Andora 1.2 live CDDVD. This is a modified version of the popular Fedora linux distribution, modified by Raymond Chan to include the Android development tools including Eclipse with all the plugins, the Android SDK, and tools like the Android emulator.

The point of a live CD DVD is that you can test the operating system on the CD DVD without installing it or making any changes whatsoever to the harddrive. That means that all of the changes you make during the session, including projects and virtual devices you created will be gone as soon as you reboot. Everything is stored in RAM.

If you're using your own machine - simply put in the CDDVD, reboot, and tell your machine to boot from the CDDVD. If you're using one of the lab machines - turn the switch to "External", put in the cdDVD, and reboot. You do not need an external harddrive.

Once it boots - click the login button. Then wait for Eclipse to start, which will happen automaticlly. Note that this environment is a lot slower than it would normally be because everything has to be read from the CDDVD. Eclipse will start automatically, wait for that.