There are various ways that you can add Products to your SI Catalog.
Add From Library
The quickest way to add Products to your Catalog is via the Add From button. Click here for details.
New Button
You can add a Product "from scratch" via the New button. Click here for details.
Importing Products
You can import a spreadsheet of Products via the Import feature. Click here for details.
Cloning Products
You can copy an existing Product via the Clone feature. Click here for details.