In order to tie a Miller's Knot, which is also known as the bag or sack knot, you should begin by wrapping the rope around the object you wish to bind: the Miller's knot is a binding knot. It is used to bind things. Next, wrap one of the free ends around it. You are, basically, wrapping one end around a second time. Loosen the part of the binding that wasn't looped twice. This is the part of the rope that you just wrapped around twice with the other end. Take the end that you looped and lace it through the space you just made. Pull it tight.