Have you used Digital File Pro before? If not you should start by going to the Universal Email page (we combined UE and DFP) and click on the link on the right that says archived documentation, in here check out some of the DFP documention.
We then have this guide that is specific to creating a download center:
This is the best resource that we have for creating a setup like this. It is not specific to the PowerStore but the ideas are the same.