Do you mean the three parts of Lizardman? You can obtain them by sneak in the bandit's camp, finish the task of lizard's egg from the witch(daytime), and look around the swamp.
You can bought wooden planks from Logan, after build the workshop (in the tools icon), you can use woods to craft wooden planks.
To obtain woods, you need a hatchet and go outside your house to chop the trees.