How can I imagine the direction of the stairs when I practice going down the stairs in a lying position when I practice going into a trance?

[CFTraveler]

When I practice going into a trance, if I practice going down the stairs in a lying position,
Am I imagining that I am walking vertically down the stairs below my body, or am I walking horizontally down the stairs below my feet?

The same way you dream you're standing up. Dissociating your physical body from your dream body. Being immersed in the environment you have created to the exclusion of external stimuli.