Staring at the stairs directly in front you, they're just to the right of the small floor plant. Walk towards the stairs just to the right of the plant. After taking the one step, turn back 180 degrees, staring at where you came from, walk to the left, hugging the railing. Taking one step to the left, you'll now be right beside the railing and if you turn to your right you'll be in front of the drum set which is directly in front of a guitar case and you're done.