Actually, this program is remarkably straightforward, and the manual is very thorough and, I think, imminently understandable. The use of this program is nearly self explanatory and a little clicking around rapidly reveals how things work. It's intuitively designed.

What's cool about this program is its flexibility: Different die types (2 to 100 sided). Hi-Low exclusion. Clusters of dice rolled simultaneously.

This allows for the simulation of many different scenarios.

A very clean, professional look, especially so for a freeware program.