You post a message to a newsgroup when you reply to an existing
message, which adds your reply to that thread of
discussion. You can try composing some test messages and replying
to them in the test groups.
You can reply to a message at the top level of a thread, starting
another second-level branch, or to one of the subordinate messages
in an existing thread. Many people reply to the last message in
the first branch, creating one straight branch in a long
line. Other messages enjoy healthy growth in several branches,
such as in newsgroups covering controversial topics like the "talk.*" hierarchy.
You can reply to a message by selecting the "reply" menu item,
which opens a new message in reply similar
to replying to an email. Your software will usually "quote" the
original message by including it in your posting. If the message
is already part of a thread, there will be several levels
of previous messages in the thread. It is considered good form
to delete all of the previous messages except the parts that you
want to reply to, often replacing the deleted portions
with the word "<snip>".
You can put your reply "inline" to the previous messages, by adding
your replies to the individual points of the previous messages
by simply adding new lines at appropriate points underneath the
text that you reply to, making inline threads of commentary like
> About this tomato plant, how tall does it grow,
About 3 to 4 feet
> and can it take a lot of sun?
It loves sun, but doesn't mind a little shade.