This photo shows the "Oak Beauty" back layer taped off so I can grout just the tree trunk and the ground area.
Here is the border area with the grout applied. ( Before wiping down). Be sure to rub the grout into all of the spaces. Let it sit for 10 or 15 mins. and then just wipe down with dry paper towels. I never use a wet sponge - just introduces more water and can cause problems.