Gorman- There are many ways to roll a chord. The roll can be very brisk and short, or stretched out, especially at the end of a phrase. The roll can start before the beat so that the top note lands on the beat, or the roll can begin on the beat and continue after. If the top or bottom notes are melody notes, then they can be played at slightly higher dynamic levels then the rest of the chord. You can also start the chord slowly and speed up the roll as it progresses. You can also make a crescendo from the bottom to the top of the chord.That’s the case with the final chord in the Parish-Alvars Serenade. If Renie indicated a roll on a chord, it probably means a longer roll then on other chords in the piece.