The "Basic" release is an image configuration containing just the essential developer tools. What one might call an "IDE" (Integrated Development Environment). This would include a user interface with browsers, etc.
If you're starting with the Basic release and want to add all of the packages to upgrade to the kitchensink Full release, install the "Upgrade to Full Image" package from SqueakMap.
Alpha versions of Squeak always follow the Basic release, not the Full release.
See Full release for a description of the three Squeak release configurations. Basic release releases will one day also be available.