I like to use large buckets, and by the time you take enough out of the cage to fit it in, it's not really worth the dismanteling the cage and her territory for. So instead when ready I move them to a large garbage pail.
I use Sand, Topsoil & Coco fiber mixed together, most is sand, but the bit of soil and coconut helps the mixture to adhere to itself. It should me misted with water, then mixed up, and misted again, and again, under the mix has a strong feel to it so that if she digs a long tunnel it will hold up and not collapse. If shes in there for extended amounts of time you'll need to mist to keep the soil moist enough.
I do mist for drinking water in the morning, no dripper as you don't want to saturate the bottom of the tubs soil. I usually place a few silkworms inside in the event that she will eat- although many will not. I usually put my computers webcam inside to spy on her. If she sees you she could abandon the whole shes digging and eventually become eggbound and die.
The laying bucket, minus the cloth that usually covers the hole not occupied by the light. The hole in the lid that is not covered by the lamp I cover with a type of perforated fabric that allows airflow.
I don't use a heat lamp, I use a florescent Coil, or a low wattage incandescent. You'll need to monitor the temperature and test a couple bulbs probably. If the amibent temperature is lower and making the sand cold, you can wrap a heating pad, cable, or heattape around the outside lower area.
Provide vines, branches, and a plant as if it were her real cage.
