The Star Wars universe is perhaps the most exhaustively defined fictional place in history.
Since it is fictional, we can play fast and loose with some details, but in general I will be relying on the Wookieepedia wiki for “accurate” information:
Our game takes place in the year 3641 ATC (After the Treaty of Coruscant). This is the seventh year of the rule of the Emperor Palpatine over the Galactic Empire, twelve years Before the Battle of Yavin where the first Death Star was destroyed. To give you a sense of when that is, in terms of the movies, Luke Skywalker is about 7 years old. The adventure starts on the desert world of Tatooine in the palace of Jabba the Hutt