The ‘forecast program’ is really a PHP script that runs on your website. There are three different scripts and the one you need is included with the Base you downloaded. Base-USA uses ‘advforecast2.php’ with the NOAA/NWS website as the source. Base-Canada uses ‘ec-forecast.php’ with Environment Canada as the source. Base-World uses ‘DS-forecast.php’ with DarkSky.net as the source of the data.
Each template (USA, Canada, World) contains all the needed scripts for that geography – you just need to have the correct icon set available on your website.