Need to add Conversion Pirate Code in Shopify

I need someone to teach me how to add this JavaScript code in Shopify. As previously we could directly add through additional Google Analytics section but Shopify has closed that for security reason. So I need someone to teach me how do I add this code in the checkout page through some other method. I own multiple stores & brands so I need to learn rather than assigning someone for every other store. Any one who can do this job kindly message me.