1) Define the attributes for your product. Example Size and Color. 2) Create your product; set Inventory Method: Track Inventory by Product Attributes; and in Product Attribute tab associate the attributes 2.1) Assign the corresponding values to each of your attributes. Example: Size: 1 and 2; and Color: Black and White 2.2)Then in the Combinations tab generate all valid attribute combinations and for each combination set the corresponding inventory parameters (Stock, Allow out of stock; SKU, etc.) Example for 1-Black: (10, true, 123-1B, etc)