Product Library
The products in your database can be loaded into any timeline as product keys. For quick access from within the Timelines editor, the libraries on the right-hand side include a Products 
tab that lists all of the products in the open database.
From the Products library, you can load database products as product keys by dragging products from the library and dropping them onto the Product track.
Tip
Products can also be dragged directly from the Matter sidebar's product library.
The first product key will be used to determine the initial product shown in your timeline. If you have not added any product keys, the product in the active viewport will be displayed instead.