Assuming you would like instructions on how to make rope reins:
First, you will need some supplies. For this project you will need about 6-8 feet of 3/4 inch rope (depending on the size of your horse's head), a lighter, and scissors. You will also need access to a hard surface to burn the rope ends on, like concrete or asphalt. If you don't have access to a hard surface, you can use the side of a pan or pot that you don't mind ruining.
Next, take your rope and cut it in half with the scissors. Once you have two pieces of rope that are equal in length, tie an overhand knot about six inches from one end of each piece of rope. Now take one end of each piece of rope and thread it through the other piece's loop until both pieces of rope are threaded through both loops (as if you were lacing up a shoe). Next, pull both pieces of rope until the knots are tight against each other and there is no slack in the ropes. This part can be tricky - if one side seems tighter than the other, try adjusting by pulling more on the looser side until everything is even.
Now it's time to singe the ends of the ropes so they don't unravel. To do this, hold an end of one rope close to the flame without actually touching it (use your fingers or pliers to hold it in place) until it starts to turn black and smoke slightly. Move it around so that all sides get evenly singed - but be careful not to actually catch fire! Repeat with remaining four ends.
Finally, take both pieces of singed rope and tie them together in an overhand knot about eight inches from one end. Trim any excess cordage so that your finished product looks neat and tidy!