Basics: You start off getting your green belt, then moving up to a black belt.
To get a belt you need to do a project.
The projects tend to follow a very standard, regimented, and systematic method of problem solving, often with a lot of statistics. Many people think its a waste because it goes through lots of steps that seem like common sense, but most people would never catch all the steps.
Great answer Sirius! Severus six sigma is great course. It helps to define the problem and truly understand it before solving it. Hope my addition was of help!-Tom