To create a new SKU for a product in a catalog:
From the ATG Control Center main navigation menu, select Catalog Management > Catalogs.
Select the product in the catalog tree.
From the menu at the top of the window, select Skus.
Click the Add Sku button.
In the dialog box, select Sku from the Item Type menu.
In the dialog box, click New Item.
Fill in the Name field (required) and any optional fields.
Click OK.