Here is an general overview of the editorial process.
A writer (often, and as appropriate, an expert on the topic) asks the editor to be assigned a given topic, or an editor asks someone to write on it. The topic is assigned (step one, assignment) and the writer goes to work. The article is also assigned a "lead reviewer" (step two, finding a lead reviewer) and there is a "blind review" exchange between this initial, lead reviewer and the writer (step three, lead review). The resulting draft article is posted on the relevant review group (or, in some cases, groups); peer reviewers suggest revisions (step four, open review). When approved by the peer reviewers and subject editor, the article is then forwarded for copyediting by two copyeditors who are assigned by the author (step five, lead copyediting). After the article has been checked and revised for good grammar, usage, etc., the completed article is posted publicly for a final, "open" copyediting by anyone interested (step six, open copyediting). The final product is then approved by the relevant area editor and the article is marked-up so that it is properly presented on the website (step seven, final approval and markup). Then the article is made "live," i.e., posted as a completed article on the website.