In trying to understand how correspondence works, there was an example in class that my prof didn't have time to through and we instead moved on, but I wanted to see how the following interaction would have worked

I've read that an uncountable set has both a countable and uncountable subsets, so I could see that the subsets of $S$ and $P(N)$ would lead to a possible 1-1 correspondence but I fail to see how I would determine the specific subsets to use to prove the problem. Perhaps I'm missing and or overlooking a factor?