It is possible that your store sells products that need to be shipped separately from each other, and therefore, you need «customized» prices for each of these products.

To apply a different shipping rates based on the product type, you will need to group the products by shipping classes  and therefore, in the "Calculation type" field of the method, select the “Per shipping class” option.

For example, let's imagine you have 3 groups of products:

• Heavy. Products with a high weight and higher rates.
• Light. Products with very low weight and very economical rates.
• Other products. These would be all the other products in the catalog that do not belong to either of the two previous groups and are subject to a regular shipping rate.

The first thing you need to do is create 2 shipping classes: Heavy and Light.

Once you have the classes created, you should assign each product to the appropriate class. If it doesn't belong to any, you don't need to do anything.

A quick way to do this if you have many products is to select all the products of a class from «Products > All Products» and, using the bulk edit action, assign the shipping class to all of them in bulk.

Finally, configure the shipping method with the 3 rates for each group of products as shown below:

This way, everything would already be configured. In this example, the shipping rate prices would be added up if a customer places a single order with mixed products from each type