On the main dashboard page in Thrive you will find a banner on the top of the page, if you click that, it will direct you to download the extension. However, if you cannot see the banner the extension can be added directly here.
The Extension is only supported in the Google Chrome web browser. The browser is available for free here.
Here is a video tutorial on how to download the extension:
Please note: There is no audio for the video guide.
Try the feature for yourself by visiting the portal here.