Open the project and explore the generated files. There are two important files that are often used during plug-in development: plugin.xml and MANIFEST.MF. They both contain metadata that describe how your plug-in should be used by the platform.

MANIFEST.MF contains basic information about your plug-in. External dependencies, name, version number etc. The plugin.xml file describes what your plug-in contributes to the platform. You should always specify your contributions otherwise they will not appear on the user interface.

Double-click on one of the above files. This will start a form editor with several pages. Explore the possibilities. Later you can add other plug-ins here you are depending on, or you can specify what Java packages you plan to provide to other plug-ins. On he first page, there are useful shortcuts to export your plug-in in a deployable format (JAR file).

Of course you can have other files inside the plug-ins. You will need .class files (containing your code of course) or image resources for icons.