What's happening here? I'm a bit confused ...

A teaser trailer for the next Star Wars film 'Rogue One: A Star Wars Story' was premiered today on Good Morning America and I gotta say, they sure are pumping these out quickly all of a sudden. I haven't even got a chance to watch the last one yet and I'm pretty sure that I heard it's already out or about to be out on DVD. Wasn't it just in theaters a couple months ago?

To say that I'm a bit confused is actually a big understatement because to be honest I have no idea what is going on here and where in the series this film comes into play. Like, why are all these films out of sequence? I'll admit I'm not huge into Star Wars but I'm pretty sure I've seen most of the films, with the exception of the Force Awakens, and I just can't seem to grasp it at the moment. I read like 7 articles today and I'm still lost. Maybe I'm in need of a Star wars marathon so I can get a handle on the stories and timelines.

For those of you who have got this down and are stoked for the next installment, enjoy the new trailer and please feel free to explain it me ha ha ha.