GMT Panzer Exp modules question

Hello, I am not expert at VASSAL as I am a infrequent gamer anymore. Anyway, I’d like to start playing GMT’s Panzer and it’s expansion sets. I downloaded the main Panzer game and it works fine. I downloaded both Panzer expansions and can’t get either to work. I am sure I am overlooking something. something simple. If someone could point me in the right direction, I would appreciate it very much.

in the module manager right click on the Panzer module and select “add extension” to load the extensions in…browse to your extension file rinse/repeat as necessary