yeah, I wouldn’t do that in the Storyboard. Also you should be using Swift 3 (not Objective C) Look into StoreKit if you want to link to something in the store. If its just a link to a website, I’m not positive Apple allows that for Message Extensions. For app extensions, they have different rules (for example, you can’t add ads in Extensions).
Whatever you do, try getting it working outside of the kit first, then integrate it. That way you can at least experiment in an empty project. Always easier.