Got it! The trial version is designed to cut out after about a minute, then it has to be reloaded. It took me so long to figure out that I needed to “Open the steam valve”, that the set had already cut out by the time I did so. When I loaded the “organ” and opened the valve IMMEDIATELY it was fine!
Administrators: you may wish to consider whether to remove this post, to avoid wasting people’s time; or whether to leave it here in case another member encounters the same problem. Thanks.