Example of parent/child attribute
Create attribute Color&size.
1. Create a parent attribute
Create main attribute Color&Size without any values. Element type: - selectbox.
2. Then create a new child attribute Size. Set Attribute Parent: Color&Size.
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Now if you go to product edit page click to add a new Color&Size global attribute to the product.
5. Add the Option's values to the Product
Then add option value like black:XS black:S white:L white:XS red:S red:L or any other combination of product you have to sell.
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In the storefront product page, customer the customers can choose combined option value
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