Hi Lyndzie,
It sounds like you have purchased fresh fava beans which are also commonly known as broad beans.
When you say 'shell' I assume you mean the pod within which the beans are contained.
Once you remove them from the pod you are 'good to go'. I steam them until soft which should take from 5 to 10 minutes.
Many people 'double peel' the fava beans. That means once they remove them from the pod they peel the skin from the fava beans.
I don't do this as I feel it's unnecessay and besides is fiddly.
I write about fava beans in my series of food tips that I write for my local community garden.
Here is the link;
https://sites.google.com/site/qhuccommunitygarden/peter-s-food-tips-from-our-gardenClick onto the food tip: F for Fava Beans