There is no special significance to suggesting the foot as the starting point. You could just as easily choose the top of one ear and then progress over the scalp and face. Where you start and the order you go in doesn’t matter. Just start wherever suits you best. Eventually, you want to closely examine the sensations in every single part of the body, first in small, highly focused areas, then in larger ones. Always maintain peripheral awareness of the breath at the abdomen as you search for any breath-related sensations in other parts of the body.
