You need to know how to use zip files on your own computer, basically. This isn't something Poser does. Once, as hborre, says you figure out what those zip files are for,  you should know which software of your computer they belong to and then you can do a search for how to install that specific software's zip files.

I would leave DAZ alone for now. Concentrate on learning one thing at a time. Study the Poser manual that came with the software to understand how it works and understand how your MAC does things. Most people here are Windows users, but there are a few that can help with specifics I imagine.