Tutorial for creating user Library?

Ok, I'm new to Quartus II and VHDL. I was reading a book on VHDL and it has a chapter on "Design Partitioning" where it talks about creating packages and then using them via the work library. But this book isn't specific to any particular software and it doesn't go into detail of how to actually create the packages and install them into the library.

As mfro suggests, I may not need to use this method anyway. I just like to work with modular designs so this "Design Partitioning" idea caught my attention. But I guess I can just include any previous entities that I've designed by simply adding the *.VHD files for those previous entities. My previous projects will become my 'library' I guess.

As I say, I'm just starting out with this so I don't really have enough experience to know what I'm doing yet.