All good so far! Install DownloadHelper, follow the instructions and you are nearly ready to go.
You will see this image appear next to the address bar at the top of the browser. Whenever you are at a page that contains video files (sometimes you need to click play on the video first) that icon will light up in colour and start spinning, click the spinning icon and a drop menu will display the name(s) of the FLV VIDEO FILE you wish to download. Click the file name and tell it where to save the file and away you go!