I got an app on my MacBook Pro and I have successfully downloaded it, but when I click on it in my library in iTunes it doesn’t enter the app. How to I get into the app?
Apps you download via the iTunes App Store cannot be run within iTunes or on your Mac for that matter. "iTunes" Apps are for iOS devices e.g. iPhone, iPad, iPod touch.
If you are looking for Apps to run on your Mac you have to open the Mac App Store located within your Application folder.
Try reporting it to the app support, they will be able to resolve your issues
maybe it is a bug then you should contact the application support
Try uninstalling(or removing) the app and re-download it to see any improvements.