Examine the hammock to see whether it has spreader bars. These are bars that spread out the hammock's support strings and flatten the surface of the hammock. If the hammock has spreader bars, it must be spread taut when it's hanging.
Choose the location for the hammock. It must be a place where you have enough room to place the posts for the hammock and the hammock itself. If the hammock has spreader bars, the posts should be at least as far apart as the length of the hammock; if it doesn't have spreader bars, the posts can be closer together. Read the manufacturer's instructions to see how far apart the posts should be placed.
Mark the holes for the posts on the ground and dig two holes 2 feet deep with a post hole digger.
Pour 4 inches of gravel into each hole and tamp it down.
Prepare a batch of concrete, following the instructions on the packaging.
Fill the first hole halfway with concrete and set a 4-by-4 post into the hole, pressing it all the way down against the gravel.
Check the post for plumb (vertically straight) and level (horizontally straight) and finish filling the hole with concrete. Set the other post the same way and allow the concrete to cure for the time specified on the packaging.
Tie the hammock to the posts and slide it up and down until it's at the point where you could sit on the edge with your feet flat on the ground.
Mark the hammock lines on the post, and remove the hammock. Drill a 1/4-inch hole through each post and screw eyebolts into each hole.
Attach the hammock to the eyebolts, following the manufacturer's instructions.