You can install the a9 Web Protection browser Extension in either Google Chrome or Microsoft Edge by visiting the download page here:
https://chrome.google.com/webstore/detail/jlgejeheelddbpdieihdpmnlodbpljnc
For Chrome, click on the [Add to Chrome] button.
For Microsoft Edge, follow the prompts to allow installation from the Chrome Web Store.
Once installed, follow these instructions to configure a9 Web Protection