Hey guys, thanks for your answers.
The rollover bit and expiration, delivery, I get it, what I was having a hard time to figure out was when the contracts started trading.
Yeah I usually use continuous contracts, but I wanted to start doing spread analysis, comparing contracts with different expiration dates to see if the prices are at premium or discount. So I wanted to know when they started trading. Oh well, how come I didn't think of opening a chart of the contracts and going back in time is beyond me, I guess I was used watching the continuous contract.