Plan out your fence line using twine and stakes. Place stakes the estimated distance apart that each fence post will be over hilly or uneven terrain, or at longer intervals where the terrain is consistent. Stretch the twine between the stakes to maintain a straight line.
Mark where fence posts will go. You can do this with marking spray paint. Space posts 10 to 30 feet apart, with posts closer together over hilly terrain. The average recommended distance is about 12 feet apart. Plan for brace posts at corners and at hill crests, with lighter duty slave posts in between. An example would be to use T-posts for brace posts, and step-in rod posts for slaves.
Determine where to place your fence controller. It should be placed so that it is convenient to you should it need to turned on or off. Electric fence controllers require a source of electricity. Where electricity is unavailable, try a battery-run or solar controller.
Plan your gates. Gate posts need to be strong and well-braced, as gates swinging on their hinges place torque on the posts. Plan gates for easy access, and determine their width based on your intended use. Use drive through gates if you need to get equipment in and out of your pasture, and walk-through gates for easy human and animal access.
Install your posts at your planned markings as needed. Metal posts can be driven in, whereas wood posts will require an auger, post-hole diggers, or equipment to push or pound them into the ground. If pushing in wood posts, use a chainsaw to first sharped the bottom end of the post.
Space strands of rope depending on the sizes of the horses you are containing and the number of strands you intend to use. For some animals, two strands at lower chest height and upper chest height is sufficient. Be certain your top strand is easily visible by the tallest horse in your pasture. Place a strand at nose height for foals.
Measure the distance between strands and mark each post for consistent installation of insulators.
Install insulators on your posts. These are made for all different posts, from clip or screw-ons for metal or rod posts to nail-in or even wire sleeves for installation on wood posts. They come in plastic or ceramic. Use special corner insulators to begin and end your fence-line. Be sure that gates are not contacted by the rope, or they could be electrified.
Run electricity across gate openings if needed by burying copper wire encased in water proof tubing and sealed with caulk to prevent water from entering it beneath the gate. Run each end of the copper wire up the gateposts to contact the bottom strand of rope fence. Use store-bought jumpers (wires and metal clamps used to "jump" current safely from one strand to another) to electrify all strands as necessary.