That's pretty much the basics covered. The movie didn't deviate all that much from the graphic novel. Biggest change was the ending with framing Dr. Manhattan instead of using the Squid.
Everything that's happend in this world between the GN and this show is only part of the show's canon.
Jesus fucking Christ, those Geiger counters going crazy at the end... More terrifying than any horror movie.
BTW, the firemen's suits are still lying in that room to this day. They are also still extremely radioactive.