About the Project Library
The project library contains the shared objects (datasets and dimensions) that exist in all of the project's cubes. You have to open a cube to see the project library.
The project library is available on the cube design canvas. Click the library icon to open the library panel.
The library shows the datasets that have been imported into the project (and optionally enhanced with calculated columns), and the logical dimensions that have modeled from those datasets.
The project library allows you to reuse enhanced datasets and logically modeled dimensions in more than one cube of a project.
Tip: Once you have imported a dataset into any cube of a project, you can always access it again from the project library (even after you remove it from the cube canvas). You do not need to import a dataset from the source connection more than once.