External adapters are those that run in independent processes separate from the StreamBase Server process. External adapters are provided in separate installation kits, and they need not be installed on the same machine running StreamBase Server.
When you install an external adapter kit, its individual documentation file is installed in streambase-install-dir/doc/adapter
If an external adapter comes with a sample project, that project only becomes available in Studio's Load StreamBase Sample dialog after the external adapter is installed.