They are the ones at the end? They are the placebo pills. They don't have any hormones in them, and while you are taking them you should get your period. But even if you don't get your period (you might not at first), or it's not over by the time you are done with the green ones, you should still start the next pack of pills right after you finish the green ones.
So always take all of the pills in order, one a day. And your period should come while you are taking the green ones, but it might take a couple months for that to happen.
Since the green pills don't have any medicine in them, you don't actually have to take them. They are just reminders so you don't get off schedule. But I take mine because I know I would get confused if I didn't.