The developing eggs will be seen as bulges on their sides. There are two ways to set up an egg laying place for them. One is to daily mist one area of the substrate so that the medium is slightly damp and check the area a couple times a day for eggs. Freshly laid eggs are slightly sticky. If the egg is fertile, it will firm up, becoming rapidly turgid, and will will feel slighly chalky to the touch.
Infertile eggs are thin and soft.
Combine 6 parts vermiculite with 4 parts water so that the vermiculate is just barely moistened. Without changing how the eggs were laid, place them carefully into the moistened vermiculite, half burying them in the medium. Place a small container of water into the vermiculite too to help keep the humidity up. A second method is to cut a piece of foam rubber to line a plastic box. Pour enough water into the box so that the foam is saturated and water just covers it.