Once you have the necessary Village Tech, the only thing that is required for the next two puzzles is patience. Once you reach the maximum village population (you've reached it on your device), you'll need to wait for some villagers to "move to the graveyard" before any more births can occur. That situation is being corrected in the v1.1 update.

The amount of time you have to wait can be unpredictable, and some people have reported waiting many, many hours. I've found that it seems to happen faster if you can leave the game running in the cradle on AC power. Of course, you still have to wait for some villagers to "leave" first.