Once you’ve completed the setup of GooglePAD and you have your asset packs downloaded, you need to use C++ to mount, set mount point, add asset registry etc.
When that’s done you’ll be able to access the content inside those Pak files.
I have a pretty extensive PDF document for my product over at ([Plugin] Easy Google PAD)
Perhaps that could help you and future developers find some answers easier, a lot of links to relevant documents and easier to read and understand descriptions of what things do. It also have references to Project Settings and such that works in correlation to the GooglePAD plugin!
I hope that helps you and others, best of luck!