[Plextalk] help with my plextalk pocket please

Hi I am trying to change the firmware on my plextalk pocket, I cannot seem to change the uk firmware to the us version, I cannot tolerate the uk tts voices, they are very hard to listen to when I read a book, I have unzipped the files from the plextalk web page but I am just getting two folders, no exe file, what am I doing wrong, is it possible my antivirus is stopping or killing the exe file? I cannot see such a message, I have tried two different sd cards, I have the pocket plugged in to the electric. Regards Adrien