Well, the easiest way is, "Oswald shot Kennedy." A more complex way would be, "Former US Marine, Lee Harvey Oswald shot President John F. Kennedy from a third floor window of the Texas School Book Repository."
The official story is exactly that, although conspiracy theorists have been debating all other versions of the events of 22 November 1963 since those events unfolded.
While this is the official assessment of the Warren Commission, and 98% of those records have been released, contrary to the 75 year seal originally placed on all of the documents, the remaining documents will not be released--a still sizable number of documents--until 2017. It is not likely that any new information will be uncovered at least until then.