I just got Juicebox Pro after watching the compelling YouTube vid in which a smart gallery is made in 5 mins with just a few flicks of the mouse.

I have not found it so easy:

Images stage
Images appear and can be captioned and moved about  as in the video.

Customise Stage
Half the screen is suddendly obliterated by a big black square. Application then becomes unresponsive and not possible to do anything further with Customise and Pucblish stages. Also the blanked out black area obscurs all the info about the Gallery folder.

It is possible to preview the gallery in the Firefox browser and it looks not bad but I have no idea how I can upload it without having got any Gallery Folder info.

I am using a windows 11 PC and have got Air and Firefox installed as advised. I have tried uninstalling and re-installing; switch off and turn back on again to no avail.

What's the problem?
Thanks
Simon