This king of kelps has not really been used alot in traditional Icelandic cooking but it is very apparent in East Asian dishes. You can use it to make the most delicious "Dashi" for example. Just gently simmer the dried Kelp after cutting a bit into it to hasten the process. It will make a beautiful and super healthy umami broth, perfect for japanese style cooking and excellent as a base for any seafood sauce or soup.
If you google Kombu recipes you will see a range of ways to incorporate this clean and super healthy kelp in a lot of different ways.