MRP forecast based scenarios,help regarding scenarios

[sandeepk6891]

I know i might be asking a basic questions.But please answer me

I have maintained forecast view of a material with consumption data of last 2 years.I ran forecast and it is good with appropriate MAD.Now i created few po's and maintained some stock.Now i ran md03 to calculate requirements for next year.Calculation is fine,it kind of plans for future forecast

1. Now my doubt is whether MRP type vv considers only forecast or also confirmed sales order for planning.

2. I also want to use sales history for forecast ,rather than consumption?What configuration needed to be done?

3. I did not use MD61 here. But i tried using it later,with planning strategy 10(make to stock).Adopted forecast values in PIR month wise. Now i can seen the screen as follows

I can see the item is planned for Forecast requirements and Independent requirements, that is basically twice.Are forecast requirements and independent requirements different?

I want to understand what is the use of MD61 or how it works?What is the correct way of doing,using md61 or without?

I am confused,Please guide me with links that explains in detail how forecast based mrp runsi.e how it estimates requirements,how it reshedules,and exception messages(Reshedule in and reschedule out) in sap.

Please note i used forecast based planning with automatic safety stock calculation,24 years consumption data,lot for lot size procedure and it is for trading goods that are procured externally