Now the core feeder compartment can be placed on the box. It has a slot for the central partition and it can be difficult to get the partition to locate correctly.
Clean the feeder tray door and check that the partition is not bent at all – straighten it if necessary.  Put the lid on and move the box to its last position in the apiary so that the bees have good access to both inputs. Open the inputs that are wide enough for a pair of bees to enter and exit simultaneously.
Add sugar syrup to feeder and leave it alone for at least 3 weeks. The new queens are very hard to spot because they are much smaller than mature queens and they also tend to take flight very easily. Rarely have I inspected a new colony and seen eggs but no queen, only to find that the queen suddenly pops up from nowhere on the frame I am looking at. This was not a miracle or an illusion ̵
A good sign of a viable core colony is that when you remove the feeder there are lots of bees noticeable. When the queen returns from a successful mating flight, she often returns a small mini swarm of accompanying bees. At this time (3 weeks) you do not need to check individual frames if it is obviously a large number of bees, as it will only disturb the colony unnecessarily and may even cause the young queen to fly away. An obvious failure on one side of the box would require the central partition to be removed to unite the colonies, but left them alone for another 3 weeks and continued to feed.