Thank you so much!I'm guessing you haven't reached the part of the game where you get wiring tools yet. You'll know it when you see it. Until then, there IS a way you can make you little blood zombie farm work. If you hold a pressure plate, wires are visible. So find an already placed wire underground (probably from a dart trap) and place pressure plate and statue on top of it.
It's even possible to make an automated statue farm if you can find a red pressure plate, because this type can be activated by enemies.