Journeymen in the Builder Council are allowed to build "online" on the test
port. OLC (OnLine Construction) rights are automatically given to all
builders who have at least one area in the game.
OLC builders still need to apply (via the applications forum) to build an
area before starting to build, so they can be assigned vnums on the test
port. A guide to most OLC commands can be found at
http://www.forgottenkingdoms.org/builders/olccommands.php but if it does not
contain contain the answer to your question, you can still ask it on the
Builder forum.
There is only so much that you can do with OLC though, and the finishing
touches have to be done offline. Once you are done with OLC and want to edit
your area by hand, you simply need to post to the area builders forum about
it. Your area will then be sent to you by e-mail or PM. From that point on,
you can no longer use OLC commands on it, and all further modifications need
to be done in the file. As for offline building, you can submit revisions of
your area file and upload it to the test port.
The review process is similar to that of areas built offline.