how the heck do i make it work properly
You need Zandronum 3.1 and Doom 2 in the folder where your Zandronum exe is. Then you can just drag and drop the pk3 (+ any mapset you want to use) into Zandronum.exe.
thanks
also do i download the installer or the archive
I'd recommend the portable (zip file with zandronum exe inside), since it's easy to keep accesible in "My Documents" instead of "Program Files"