Now it is time for a bit of math. Consider a three-row pyramid. If we want it centered, it would look something like:
··#··
·###·
#####
Empty spaces have been replaced with interpuncts, or middle dots, for readability. If you extrapolate the pattern, you can see that the spaces at the beginning and end of a row follow a pattern.
Update your blank space strings to be repeated rowCount - rowNumber times.
Ok, then there has to be some parts of the instructions you do understand? Can you be more specific about what in the instructions you don’t understand and why?