It sounds like you haven't quite grokked the overall mindset of Archive::Tar, which uses objects rather than simple perl data types like strings and hashes.

So, you start with the "tar container" object (the thing returned by Archive::Tar::new), and use its methods to do things -- e.g., open a tar file and fetch the various "tar content" objects (directories and files), and then use the methods of those objects to see their various attributes (data content of files, dates, owners, permissions, etc).

In case it helps, I posted a review of this module a while back. If you have any questions after reading that, show us some more detail of what you hope to accomplish, what you've actually tried, and how that's falling short. (I'm hoping that my review hasn't become terribly outdated due to module updates...)