Use this screen to configure categories of sizes used to describe your products. You can create several different size categories, each with their own specific sizes. For example, you might have an Adult category, with adult sizes ranging from Small to X-Large, and a Youth category, with sizes ranging from Youth Small to Youth Large.
Navigate to the Storefront - Product Manager.
Click Configure - Sizes.
Select Add Size Category to add a new category of sizes.
Once you've added a category, select the Sizes icon to add and manage the specific sizes associated with that category.
On the Size screen for the category you selected, select Add Size to add a new size in this category.
Like product colors, categories and sizes you add will only apply if you configure your product to have size variations. The list of sizes will be available as a drop-down list when configuring the product.