This command displays a progress bar on the screen.
Turn on the progress bar at 0.0.
Where n is a number between 0.0 and 1.0 indicating the amount of progress.
Turn off the progress bar.
You don't want to use the Progress command in every iteration of a loop since it performs a Wait 1 to allow the screen to update. Use the progress command about every 100 iterations or so. Test it and adjust as needed.