burying/sinking earthtainer in the ground

[vintagepatch]

I have question about how deep should I burying/sink the earthainer? The beds are raised and surrounded by limestone. I know the totes should be level. No rocks or debris under the tote. How do I keep the overflow from being blocked? Should I use pea gravel underneath or flat bricks? Here is a image of what being done so far.

Thanks,

Mary