Fields in Master Recipes

Hello

Could anyone please let me know what are these fields used for in Master Recipe General data screen .

1. what is the control key used for in master recipe and resource creation process.

2. how is capacity category and control key is related in scheduling and costing.

3.where do we create control recipes or are they generated in back ground from process orders and what level are they created.

4.what is a production version and why is it used in master recipes.

5.what is standard value key and its relevance in resource creation.

I'm very new to PP-PI and please explain me in simple flow to understand the process and relevance

Thanks in advance

Raghu M