How much organics and what kind?

I know about horse manure, but there are many kinds: two-part, three-part, pelletized, with "padding" etc.

Even gypsum is a problem, there is grey gypsum, white gypsum, gypsum for building, for electricians...

I know it's easy for people who grow stuff and know the products but it's hours of research to get every step done for me.