This website uses PDF files. Due to security concerns, browser developers have removed and are continuing to remove certain functionalities. Reading a PDF file in the browser has been removed. The PDF file must be opened in Adobe Acrobat Reader, https://get.adobe.com/reader/. In the past, when you click on a PDF file, the browser would start a small program inside the browser to view the file. Now, the browser must be configured to open the file in a separate Adobe Acrobat Reader program. You may need to change the behavior of your browser. Below are links that may help resolve your issue.
Microsoft has 2 browsers, Internet Explore ( the one we are used to ) and Microsoft Edge. Visit https://www.google.com/search?q=start+IE+in+windows+10&ie=&oe=#q=start+IE+in+windows+10&start=10https://www.google.com/search?q=start+IE+in+windows+10&ie=&oe=#q=start+IE+in+windows+10&start=10