Ok, this is a dumb question, but can somebody please explain the concept of index futures? I read about futures re commodities and it makes sense but I can't understand how it applies to index futures? I opened e-mini futures (ES) on my chart, to me trading it is just like a stock, 1 tick-$12.50, and it looks like it is very volatile, so I keep losing money in my paper a/c. Also, I can't understand how the expiry date works here? Can somebody recommend a good book on e-minis or mini-dow?