Back in '94 and '95 I had two females lay 3 clutches over that 2 year period.
I placed about 18 inches of soil, mixed with peat moss, along with a few small tropical plants planted around the edges, inside a large laundry tub (24" in diameter, about 20" tall) at the base of their large ficus tree.
When it was time, the female simply climbed down into the large tub and dug her hole.
The most important thing is not to disturb her during this process, so give her as much privacy as you can.
Keep her well hydrated, especially during the last few months of her gravidity. I would shower my females for an hour straight, 2 times per day, during the last few months of gravidity. I never had to use any drugs to induce egg laying with my parsoni.
I wish you the best of luck.