When it gets dark tonight, take a very bright flashlight into a dark room, and cup your hands around it to funnel all the light through the egg. If the eggs are alive, you should see mostly dark on one side and, in the large end, a bright area that is the air cell. In the air cell, you may see a shadow that is the beak of the baby. If so, you should be able to watch it for a minute or two and see it move. If there is no shadow in the air cell, then you may be able to see the line between air cell and baby moving, which is the baby pushing against the inner membrane. Watch until you see movement one way or another.
Candle each of them like that, and you should start to see a pattern. This will tell you whether it's even worth trying. It's possible the hens abandoned the eggs because they're no good. But it's also possible that they *are* good and your heat lamp may help them hatch.
If they're alive, you need to keep them around 98 degrees (more or less by a couple degrees is okay, but keep it between 96 and 102 as much as possible--anything higher can be dangerous), and you need to keep the air around them humid. You'll have to create some sort of enclosure for them that will contain the humidity but still let air flow through. A plastic container with holes punched might work. Humidity can be achieved with a bunch of damp rags or sponges, but don't let them touch the egg itself as they can leach heat from the egg and cause it to chill.
You're going to have to do a bunch of "babysitting" to get those eggs to hatch. It's hard to keep temps & humidity where they need to be. But many people have done it, and I wish you the best of luck!
