If you haven't yet created your inventory and you want to from PC then you can.
Make sure you have 'Add by ID' enabled - if not ask support
1. click Add by ID
2. Then simply choose your Brand and SKU via the 'Add by ID' button.
3. hit search
4. and finally ADD! - it will automatically add all three top layers for you, each decorated with images and descriptions:
Category
Product Family
Product Line
In this example I'm adding a Specialized Aesthos Comp - with SKU 97222-49
