See Video - Sounds great! (sorry about white noise, Fan was on)

To properly use a Guda drum (a type of steel tongue drum), place it on your lap or a stand with the notes facing up. Position the larger, lower notes closer to you and the higher notes farther away. Strike the tongues gently with your fingertips or mallets, allowing your hands to bounce off quickly for a clear resonance.

I found it lying flat does produce as nice of a sound than if you hang it.