Good question. What you want to do is target something on the page and then change the target rules to specify what you need to find, such as ORGANOGRAM.pdf or whatever the link text is. To show that this works, I targeted a link on this page -- https://www.socketmobile.com/support/downloads/product-support -- namely the Get Started Scanner Guide (EN), and then edited the rules of that action to search for a link that was near the bottom, Regulatory Compliance (EN). In the action, I sent a Click action and it opens the correct PDF in a new window. Attaching a screenshot of the rule.

HTH,

Mike