Because a post-and-rail fence is made of widely spaced slats, it's best used to contain livestock or to mark property. It is not the fence to use if you are looking for privacy. This fence is rather simple to put up because its slats lay horizontally instead of vertically. Post-and-rail fences also don't require a lot of hardware to install. You should be able to install the fence for the entire perimeter of the backyard in just one weekend.
Plan out where you would like your fence posts to go. You will want the distance between the posts to be 2 inches shorter than the length of each rail to allow for a slight overlap. Each time you determine where a post should go, place a stake in the ground. This will mark the spot and help you find out how soft the ground is. Don't lay your fence if the ground is too damp, or the stakes will not stand upright.
Check to make sure all of your stakes are in alignment so your fence will be straight. Starting at one end of your fence, tie string to the stake. Then, pull the string tight and continue to the next stake, looping the string around each stake as you go. If one of the stakes is not perfectly in line, move it until it is.
Take the stakes out one by one. Each time you remove one, use the post hole digger to create a hole that's half an inch wider than the base of your posts in all four directions and a third of the post height. (This means it will be 1-inch square wider in total.) Put 2 inches of gravel in the bottom of each hole to help with drainage.
Place one of your posts in each of the holes you dug. The holes for the rails (two in each post) should face to the sides, not in toward the yard. Double-check the distance between each post with the tape measure. If any are too close or too far apart, you can't install the rails right. Fix the posts if necessary before you tamp them in.
Put as much soil as you need in each hole to secure the posts tight. Then, tamp the soil by holding the top 6 inches of the tamper's handle and slamming the base on the ground where you added soil.
Place your rails in your fence by sliding them through the holes in the posts. Each rail will sit with one end in one post and another in a second one. Check each rail with the level as you put it in to make sure it's straight. The posts are cut so that two can meet in each hole, except for the corner and end posts, which are only half-drilled.