Unfold and place the hammock on the ground. Run a stringline through the middle of the hammock and well beyond the position of the posts. Mark out the post holes, allowing at least half a metre at each end of the hammock for stretching. Then dig a rectangular-shaped hole. Allow plenty of room for a decent amount of concrete - I used 100kg of concrete in each hole.
Insert each sleeper into the hole and line up, using the stringline. I used one 2.1m sleeper and one 2.4m sleeper but I recommend using the longest sleepers possible.
Even though the sleepers are on an angle, front to back, they must still be level from side to side. I used a brace and a quick-grip clamp to hold the sleeper in position while I poured in the water and the extra strength quick-set concrete.
Once the concrete has set, trim the tops off of each sleeper so they are level, then drill a hole through the middle of each. Make sure this hole is as high up as possible. Once you are in your hammock it will sag a lot.
Dress the sleeper with a plane and sand then give it two good coats of stain. Add another couple in a few months.
I used stainless steel rings to make untying the rope and adjusting the hammock easy once it has stretched. This will need to be done often during the first summer - the more you lie in it, the quicker the stretching process, so make sure you put your feet up.