How does it work?
MonteCarlito is a VBA macro; just open the MonteCarlito Excel file along with your actual worksheets to use it.
How to start a Monte Carlo sim?
Put the number of desired Monte Carlo paths next to a cell containing a randomly fluctuating formula; select the two cells, along with some cells below; then press [Ctrl+W]. (The MonteCarlito Excel file contains a more detailed tutorial.)
How to create histograms?
Set the format of the cell containing the number of paths to bold before starting the simulation.
How to speed it up?
Enter a negative number of paths. This minimizes Excel during simulations, and avoids costly window refreshes.