Use a measuring wheel to determine the exact measurements of the area you want to fence in. Place a stake in the ground every 8 or 10 feet, depending on how far apart you want the fence posts to be. Keep a count of how many stakes you have used.
Cut a 4-by-4 piece of lumber to a length equal to the height of the fence, plus 30 inches. If the fence will be over 6 feet tall, add 36 inches instead. Cut one 4-by-4 for every stake that you used.
Make a horizontal pencil line on a 4-by-4, 30 inches up from the bottom, or 36 inches, depending on how much you added to the fence height when you cut the lumber. Extend this line all the way around the post.
Place a small dot in the middle of one side of the post, 12 inches above the line you just made. Then place another dot 3 1/2 inches above that. Place a third dot on the same side of the post but 2 inches below the top, and another 3 1/2 inches below that one. These marks are for the outline of the top and bottom rails of the fence. Make additional sets of dots, with each set having 3 1/2 inches between the dots, for every additional rail you want to add. Space these sets evenly between the top and bottom sets.
Clamp the post into place. Use the 2-inch drill bit to create a hole in the post between every set of two marks. Take a scrap piece of 2-by-4 and make sure it will fit in each hole before you continue.
Repeat this process for every post. Place the first post over the second and draw the outline of the holes, so you don't have to measure the marks on the other posts. When you go to make a corner post, only drill halfway through, then flip the post to an adjacent side and repeat the process.
Count up how many 2-by-4 boards you will need and cut them to length, if required.
Dig a hole, using the post hole digger, where each stake is located. The hole needs to be 30 inches deep, or 36 inches for larger fences.
Place the first fence post into a hole. Place your level against the post and make sure it is completely straight. Backfill the hole with dirt, keeping the post straight the entire time. Use the tamper to press down the dirt around the base of the post.
Place the next post into its hole, and then place the rails between the first and second posts. Ensure the second post is straight and backfill the dirt around the post. Continue this process until the entire fence is up.