PressPass is simple

Users are directed to your news site via Google News, facebook, or other link.

When they arrive, they might be blocked by a paywall. 

Without PressPass, they either subscribe, or they don't read your article.

With it, they're either taken right to the article for a small fee, or, they are presented with a link they can click to read the article if they like.

Once they've gone to the article, the fee is deducted from their balance, maintained by PressPass, and, passed on to you.