Hold the bosal with the knot or ball in front of you. Place the loop like it's a basketball hoop, horizontal to the ground. Grab the knot or ball in your right hand to hold it in place. Keep in mind that you may need to rearrange or grab the other end of the bosal as you wrap the rope around it.[
Draw the tassel or end of the mecate through the bosal. Grab the end of the mecate, which may be a tassel and put it through the hoop in the bosal. Pull it up against the bosal's knot at the bottom with the mecate's end hanging just under it. Hold it in place with your hand. You only need to leave a little bit of the mecate out, about 1 inch (2.5 cm) before the tassel.
Wrap the mecate rope around the bosal going clockwise. Take the long end of the rope and wrap it around both sides of the bosal that extend from the ball or knot. Wrap it right up against the knot as close as you can.
Pull the reins through the bosal, moving from the back to the front. Make a "U" with the long end of the rope and set it behind the bosal. Pinch the "U" through the bosal and pull it through to the front, over the wrapped ropes below. Keep pulling until it's long enough to act as reins for your horse, maybe 5 to 6 feet (1.5 to 1.8 m) in length.
Wrap the mecate rope around the bosal 2 more times. Wrap it going the same direction as you did before, clockwise. Pull each wrap tight up against the rope below on the bosal so that it will hold the reins and knots in place.
Push the lead line through the opening from back to front. Look at the last 2 loops you made. You should see they make an opening in the back underneath them. Go over the loops in the front and then through the loops and underneath them as you pull the line out the back.
Tighten up the knot. Pull on the lead line to tighten it up, then use your hands to twist the loops at the top. Push the excess rope from the loops into the lead line and pull it tight again. Keep twisting and tightening until it's as tight as you can get it.