The First Puzzle
To complete the first puzzle, you must build a fire in the fire pit. To do this, make one of your villagers collect dry wood from the wood pile in the southwestern area of the village. Then get a villager to collect dry grass, which can be found to the west of the village near the coconut trees. Once you have both the firewood and dry grass in the fire pit, drag over a villager and command him to light the fire. Make sure a villager puts more firewood and dry grass in the fire pit from time to time so that the fire does not go out.
The Second Puzzle
Solving the second puzzle involves constructing a dam so that you can use water for farming. First you must purchase Level 2 of Engineering Tech. Once you have done this, move a villager over to the rocks located at the lower portion of the stream. A message saying "He could probably build a dam here" should appear, and then you must command the villager to build a dam. Water is then diverted to an area where it can be used for irrigation.
The Third Puzzle
The third puzzle is solved by making one of your villagers construct a scarecrow to protect the crops being grown. Begin by moving either an adept or master farmer over to the northwestern area of the village that contains twisted pieces of wood and vines. When your adept or master farmer is there, command him to construct a scarecrow. You will have to visit the area twice before the scarecrow is fully completed.
The Fourth Puzzle
The fourth puzzle is to create a cutting tool so that your villagers can cut away unwanted vegetation in the village. First you must purchase Level 2 of Exploration Tech, and then drag a master scientist to the north of the village. Look around, and he will soon see soon things that look like spear tips among the rocks. Once he has found them, take him to the area with twisted wood and vines where you made the scarecrow. Here he will collect materials. Next, go back to where you saw spear tip-like items, and the master scientist will construct a cutting tool.