Most people do it one of two ways.
Some people like to use the program right away when they get it. Others want to give themselves more clean days before starting the program. We have seen people do it both ways effectively. The advantage or doing the program right away is that after completion of the program you can test yourself. And if you come back positive then you have time to either get more detox or work on another solution. The advantage of waiting closer to the day you need to be clean is that the more clean that puts you in a better position of passing.