You can use the Inputs pane to add input files and directories as sources for files that you add to packages. This pane contains two subpanes: one view that allows you to set the dependency hierarchy and one view show the source files currently exist on disk. Each subpane is a different representation of the same set of files. All files which are added to packages in the Editor pane must be originate from the Inputs pane.
You can add three different types of inputs:
Use the Inputs toolbar options to add or remove inputs for a solution, to build packages, to set dependencies for packages, and add installation constraints for packages.