You can play around with the Dragon Age Keep in open beta now. Go to the website, log in with your Origin account.
The Keep provides an interactive tapestry with which you can create and manipulate the choices you made in previous Dragon Age games. They're then exportable to any version of Dragon Age: Inquisition.
Saves from previous Dragon Age games can't be imported into Inquisition nor can they directly be imported into the Keep. However, information from the previous games - such as trophies/Achievements, and character profiles - will be synchronised, filling much of the tapestry for you.
That done, you can tweak the choices you wish - and there are lots of them. I didn't play much of the DLC but I can make choices now as if I did (who can I kill off?).
At any time you can play a voiced, animated version of your story that strings together your choices- it sounds like the voice of companion Varric.
The Keep offers completely new Dragon Age players a chance to flick through the history books before Inquisition, and, if they wish, tailor things here or there to their suiting. But you needn't use the Keep at all, and start from a default world state in Inquisition instead (the impact of saved games in the Dragon Age series isn't as direct as in Mass Effect).
Dragon Age: Inquisition arrives 21st November on a spread of old and new platforms: PS4 & Xbox One, PS3 & Xbox 360 and, of course, PC.