dbpropp

I just found out that PDN has a lot of downloads available (I love PDN but never knew there were add-ons - now I'm Really in love!). I downloaded an add-on package, expecting to see a .exe file or something to install it. Of course, it just contained several .DLL files. I don't know how to use these. Do i just copy them to the PDN subdirectory? Create an "add-ons" directory and put them there? Or what? I know this is a very simple question and I apologize for my ignorance. :-) Thanks!!