That guy who guided you to your seat? He's called an usher. You most often see ushers at movie theaters and weddings.
An usher is someone with the job of helping people find their seats. At the movies, ushers take your tickets and tell you where to go. At some theaters and sports venues, the ushers might actually take you to your seat — they usher you there. If you're an usher in a wedding party, it's your job to walk guests down the aisle and to their seats. The doorkeeper at a courtroom or legislative chamber is called an usher, too.