user- session management nodejs

I have been trying to get my head around nodeJS and expressJS, and I found some really good examples.

I could understand chat in nodeJS to, but I could not figure out 1 or 2 modules.

Is there a really good example that explains how to do it?

This is the first time I am working with it.

There are similar questions which may help, as well as blog posts on the details of the authentication process.