Lawsuits (and most arbitrations, really) go through three or four main phases:
PLEADINGS: The filing of the complaint, the answer to the complaint, any counter-claims (and more exotic pleadings, like cross-claims and third-party complaints) take place at the beginning of the case. Also, disputes over the sufficiency of the complaint, jurisdiction, and similar foundational issues, or attempts to change courts, are usually handled at this time.
DISCOVERY: Do you know what ennui is? A kind of anxious boredom, or perhaps bored anxiousness? That pretty accurately describes the discovery stage. In this stage, the parties are allowed to get information from each other and from non-parties (often in ths same manner as a dentist extracts a tooth) in a manner that is both formalized and informal, usually away from the oversight of the courts (which dislike getting too involved). One may request documents (including electronically stored information) from your adversaries, make your adversaries answer written questions, take depositions (like interviews but involuntary and under oath), inspect property and IT equipment, and so forth. Of course, your adversaries get to do the same to you. During this time, once enough discovery has been taken, you or your adversary might move for “summary judgment,” on grounds that, if you limit the legal analysis to just the undisputed facts, there’s only one way a jury could go. As you can imagine, such motions are very elaborate and time-consuming, but still much less so than trial.
TRIAL: You’ve seen these on TV. In real life, they’re less exciting, and the lawyers generally have to follow the various rules of procedure and evidence (unlike their TV counterparts, who apparently operated by an entirely different set of rules). They can last for a day or two (rarely), or go on for weeks, depending on the needs of the case. In addition to spending all day at the courthouse, your lawyers will also be busily working on trial briefs, jury instructions, evidentiary motions (known as “motions in limine”), and even more elaborate motions (such as for a new trial).
APPEAL: Even after the trial, it’s not necessarily over, since the losing party (and sometimes the winning party) can appeal. Appeals consist mainly of long briefs written by the lawyers, plus a short argument before a 3-judge panel. Appeals are not the time to raise new legal theories or introduce new evidence! The point of appeals is to correct mistakes made by the trial court, not to re-litigate the case. Their scope is, therefore, limited to the “record”: the evidence that was recorded at trial, and the arguments that were presented during litigation. Most appeals uphold the original verdict, but some result in a complete reversal (*i.e.*, the winners and losers essentially trade positions), and still others are sent back to the lower court for a new trial (oh, joy!).