When I unzip the GPTPro download, I open the folder and I can’t install GptPro.

You shouldn't be opening the inner folders to try and install. You need to ensure you're at the top-level folder named gpt_pro (version #). Select that top-level folder and then continue with the installation process. In the installation video, we demonstrate that you must install from the top-level folder. Please refer to the image below for clarification.