Put some cotton in, then the net and seeds. But it is also working without cotton or without net - however both is reducing the evaporation and ensure moist environment for the seedlings.
The net makes it easier to distribute them equally. If you need to separate and plant them later you may remove the net directly after distributing - as it becomes difficult when roots grow through.
The Tank will ensure the base is always moist (until there is water left in the tank - so print in something translucent).
Jack
