Sending the message has actually nothing to do with Patcher. It depends on the method you use for sending mails, but will usually be done via a C-c C-c command of some sort. On thing to note however: if you've committed your changes via Patcher, the message has been slightly modified: the subject line now reads “[COMMIT] something sensible here” instead of “[PATCH] something sensible here”, and a short commit notice has been inserted just at the beginning of the message's body.
That's it. That was easy. Congratulations on your first shot at Patcher, anyway! Of course, Patcher is much more powerful and customizable than what has been described in this chapter. For a complete documentation on how to use and customize Patcher, please refer to User Manual.