Cut a large straw into 3 or 4 pieces and place them at the low points in the bottom of the hollowed stump.
If I had landscape fabric on hand, I would have laid that down prior to pouring the cement. So I recommend doing that first, then cut holes to fit over the straws.
Mix the cement to the consistency of a thick milkshake. I poured some in the hole and then spread it around with my gloved hand.
Once the cement has cured, you can begin layering the garden materials for the mini succulent garden.