Shopify plus checkout page customization

I want to add 2 drop-down fields in the checkout page of my Shopify store and some functionality with the shipping fee. It should have:
- one Dropdown field having a list
- another Dropdown field that depend on the option chosen in the first drop-down list
- The Dynamic shipping fee should depend on the first list to be added

The shipping fees should depend on the selection of the first dropdown list. Further information is in the attached document.

Thanks