Being in the body means having awareness of all the parts of it from your toes to your abdomen to the crown of your head, and maybe even some of the other layers of your energy field.
How we experience the body is how we experience the world. The body is a sense organ. Primarily we are conscious of seeing, hearing, tasting, smelling, feeling with the skin. Imagine being able to sense the world with your liver, kidneys, or spleen. Your inner organ are sense organs too(Guardian Angels by Rudolph Steiner)!