Lie on a carpeted floor on your back without any pillows or anything else, unless it hurts you to do so. In that case use a pillow under your knees or wherever you might need one. Lying on the floor, get into a rhythmic breathing pattern. In and out through the nose. You will either want to count internally (1,2,3-1,2,3) on the inhale and exhale, or repeat a "key word" of some sort internally. The key word should be a word with a positive connotation. (Relaxed, Relaxed) (Confident, Confident) or in your case you might say (Sleepy, Sleepy). You will do well to also have a sense of your heartbeat during this time period and include the rhythm of your heartbeat in with your breath and the key word. Heartbeat, breath, and key word, like a musical trio playing in harmony.