Pro Sites - how do you actually use it?

I've looked at the usage instructions for the plugin and I've read the tutorial on your blog. Both explain how to install and configure the plugin and how it works.

But neither of them explain how you actually use the plugin. It's installed. It's configured. How do I engage users in creating sites and going through the process? And where will users manage their subscriptions and all that goodness?

I think the documentation needs some major improvement. In the meantime - can you please explain how to actually use this plugin? I have a fresh multisite install with just the root site. Did I miss something? I feel confused.