The add-on detects the resources you are browsing and tells if the library has a subscription on that particular journal. So you don't have to go through SöderScholar.

Here's how: search for the Chrome web store. Type "libkey nomad" in the search box and download the extension. Then select Södertörn University from the drop-down list, and you're done!

Note that you still need to go to SöderScholar in order to find e-books and other e-resources.