dont panic, panicky!! its quite easy. imagine the foot as a body... see how it dips in the middle, sort of like a waist and then goes out again, like hips? also, the knobbly bit on the lateral edge (cuboid notch, isnt it), the waistline starts round about there.
[link]http://www.rosieweb.pwp.blueyonder.co.uk/Charts.htm[/link]
[link]http://www.rosieweb.pwp.blueyonder.co.uk/Reflexology.htm[/link]
this second link doesnt show the waist line, i thought it did, but its sort of across the middle of the green area.
you will soon get the hang of it, really!