The DUI pre-trial hearing is the court appearance in which your DUI case is often resolved, or a plea agreement is reached with the prosecutor. If an agreement or plea bargain is not reached the case is normally set for trial. The next step is a pre-trial motions hearing. (see previous post)
You will often have several of these hearings and they are typically very quick. Your attorney will ask you to sign a speedy trial waiver each time to get a continuance. Typically, your attorney wants more time to investigate your case (i.e. interview the officer, talk to witnesses, visit the scene, review the breath test records etc.) and/or negotiate with the prosecutor. Don't be alarmed if you have many of these hearings - it is very normal.