Action: Drop your villagers on 5 herbs around the island. It does not have to be the same villager so all 5 herbs can be studied the same time by different villagers. This is the first puzzle I solve as soon as I start a new game as there are no requirements for this puzzle. Here are the locations of the plants:
Green herb on the upper left side.
Red and yellow herb on the top toward the left.
Green cactus on the top center.
White herb on a stick on the right near the top.
Pink herb on the right near the bottom.
Description: "After thoroughly investigating Isola's indigenous herbs, your villagers have mastered their healing powers. Your healers are more effective than ever!"