Custom object and master detail field are two steps that should be configured to meet this requirement.
Custom object can be used to create a new object for shoe design that can store information about different designs and stages. Master detail field can be used to create a relationship between Product and Shoe Design that prevents deletion of Shoe Design records and allows multiple designs for one product. References:
https://help.salesforce.com/s/articleView?id=sf.customize_customobjects.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.relationships_considerations.htm&type=5