Where do I connect a C-wire on my Honeywell TrueZone board?
According to the install instructions, the zone board has dedicated R and C power terminals which should be connected to the corresponding transformer wires from the furnace, or to a dedicated 24VAC transformer if the furnace's transformer is not being used.  If your furnace doesn't provide a C wire (typically blue), update your post with pictures of the setup and we can provide more help.