documentation on the lower left of the screen mainpage, but really click education in your country and top left you can set prioritys, which if you rational correctly can workout well, but you need to raise the index for better effects, and usually want to set higher for the shortage of workers and something to keep a steady gain of others workers to prevent uneven shortages.
And agriculture, lol corn sells alot, alot of people buy it. No time soon is corn going out of buisness, alot of it growing and going, back into the ground from stool(really though HEHE! cattle feed needs corn, and corn is in high demand, nasty cows). Self sustaining in this game is a no no. You gotta just build effective corperations, which they vary really but are more surplus in industry/advanced, make profits to but what you require. Doesent mean you cant make your own supplie contracts but it will drain your spending space if its too high.