The best way to use it, is to use a drawn comb and cut a section out of it, insert the cage. In my trials I, too, let them build the comb themselves. But that is not a good idea. Better insert it into an existing comb. Preferably from the same hive.
In my second trial I even harvested more cells with larvae than I remembered.
Became some nice cells.
And nice queens out of the Nicot cage.
Still grafting is much easier, less complicated and you can do more queens in less time and with less effort.