He tells me he's building a tree feller and they're people who collect eels in the mud and cockles, I can't, any help?

Hi, I'm in the story and they've moved me to a small island, and I can't progress. It tells me to build a tree cutter, but they're people who collect eels and cockles in the mud. I can't create someone who chops down trees; the option isn't available in the build menu, and I can't continue the story. Does anyone know how I can do this? Any help would be appreciated.