So how did I get my villagers to start construction on a plank and a rock? Even the farmers and scientists are working on it - the only master builder I had was nursing a baby!

Or are you saying that with a Master Builder available, the villagers will figure it out on their own? I must admit, it's terribly addictive having total control over these little people - there was a Twilight Zone (or its ilk) onetime suggesting that humanity was merely part of a grand cosmic game played by some superior alien species. That's kind of what this feels like...lol.