Before starting press the stone button by the repeater clock once, or the window to the zombie will never open.
The schematic has no floor: place the farm straight on the ground, away from villages. Add the villagers (3 per module), the zombie in a minecart and the lava in the chamber yourself. Place only the water sources: 16 on the module's platform and 1 in the chamber; the rest flows by itself.
Turn on “Hints” in the 3D view: it marks where the villagers and the zombie go, where to pour water and lava, and which button to press.
More about the farm, its output and materials — in the article on the BeezzLand blog.
