Simple question about submitting a patch

I'm ready to submit my first patch to the help files, but I find the wiki a
bit confusing.

Development/gerrit/SubmitPatch says "As a casual contributor your patch
needs to have the same email address as your gerrit account has or you will
not be allowed to push." How does a patch have an email address? And what is
my gerrit account address - I log in via Launchpad so I assume that this is
the address that I should use.

Also, is there any convention about the message content on the git commit,
like the author's name?