How do I register as a VDI in France and how is tax / social charges calculated?

I am just registering with forever living products as a distributer in France. At the moment I have set it up as an English business as I needed everything in English until I am more confident with my French. We are however, likely to be permanently resident in France this year. The Paris company have explained:

A new distributor must register himself as a Vendeur à Domicile Indépendant (VDI), i.e. an independent home sales representative, first. Regarding your income to declare and tax to pay, we distinguish two income as follows:

1. Estimated turnover = resale purchases + margin (based on customer price recommended). NB: to find the real turnover real, VDI must consider the total collected from his customers.
2. Group Bonus + NDP (generally all that is perceived by a third person).

My Questions are:

1. As a VDI what percentages of tax and social charges are applied and when are they submitted? If for example my total turnover was 30,000 euros each year and within that my 30% sales commission was 9,000 euros. Plus there was say 2,000 euros a year in group bonus what would the calculations be and when would the payments be made?
2. At what point, if any in the business, would this VDI status need to change into auto-entrepreneur, or perhaps the Reel Simplifie system?