Complex sentence: Greenwald has co-produced and appeared on ex-Panic! at the Disco members, Ryan Ross and Jon Walker's new band, The Young Veins debut record, "Take A Vacation!".
Split into simpler sentences: Greenwald has co-produced and appeared on ex-Panic! At The Disco members, Ryan Ross and Jon Walker's new band, The Young Veins debut record, "Take A Vacation!".