At the Hachiko exit of Shibuya station, you'll see the big Hachiko crossing (with the big Tsutaya and Starbucks). Take the left street towards 109. 109 is in the centre of a Y-intersection, take the right street (Bunkamura-dori) and walk until you get to Bunkamura at the end. Orchard Hall is in the Bunkamura complex.