This is the Update Site URL

AgileJ StructureViews installs using the Eclipse update manager which downloads and installs plugin files.

If you can see this page then it means that you have clicked on the update site URL in a browser.

What you need to do is navigate back and instead of clicking on the link, copy it to your clipboard then with Eclipse running do:

Help -> Install New Software

and paste in the link which brought you to this page.

Please see the installation section in the documentation for full details.