Each student has come to New York having won a regional award for a specific performance. They arrive prepared with a song from that show to perform, not to mention their costume in tow. A group of coaches–this year that included the musical theater performers Liz Callaway and Leslie Odom Jr. who, yes, was on “Smash”–split them into groups where they create medley around their songs, much like the openers on “American Idol.”