Thanks for reaching out!
It is a terrific idea to add color swatches to your product pages as this can definitely encourage a purchase. The Debut theme currently does not have a built in feature for color swatches at this moment. With that being said, we do have various third-party applications that will allow you to have this feature on the store. You can search for an application on the Shopify App Store. Here are a few examples:
In regards to adding boxes for the sizes of the products, we can add a table to the products description. In order to do this, we will need to navigate to Products and select a product you wish to add the table to. In the product description section, you should be able to insert table and begin to customize it.
Let me know if you have any questions.