Call Where Used in Nash

Good day all.  How can I call Where Used in Nash?  We have a lot documents that we need to identify where they are used and it would be a real pain to have to go through each one, open it, select Where Used, and then figure out the contents.  I have found the script in Client/Scripts, but I'm not sure how to call it.  

If someone has a better solution to getting this information I would love to hear it.  Thank you.