Please be using the Firefox browser when following the directions on this page.
If you don't have Firefox installed, you can ignore this page altogether.
Firefox Certificate Installation
Firefox has its own certificate management system, which means it doesn't use the operating system's SSL store. So for Firefox, click the green padlock icon to install the root SSL certificate.
You will see a dialog box like so:
Make sure you check "Trust this CA to identify websites.", and click OK.