The simplest way to install Eucalyptus is to install Cloud-in-a-Box. It is also the least like an actual cloud, but it's a great way to learn the basics about how Eucalyptus works. All components are installed in a single system, and most of the configuration is handled automatically.
Normally, you would download a credentials file and use it to configure the client tools. As part of the Faststart process, credentials are downloaded and pre-installed for you. These credentials, are available in /root/credentials.zip on your Cloud-in-a-Box system.