Gosh, where to start...?
I don't have the answers... I don't claim to know what really happened, it's more about what didn't happen.
LHO was a boyscout, fascinated with being a secret agent, joined the marines, was selected to work as a radio operator for one of the US' most top secret programs: the U2 spy planes. When Gary Powers was shot down over the USSR, his secret mission departed from the same base Oswald was working at. He learned Russian very quickly, was allowed to "defect" (a person who undoubtedly had sensitive information about our spy plane program) and return to the USA during the height of the cold War, and for his actions he received nothing but a welcome home.
Then he proceeds to go to New Orleans where he is known to associate with former Naval intelligence figures (once a spook..) as well as anti-Castro Cubans....
Meanwhile he is closely befriended by an older and wealthy couple, the DeMorenshildts.... part of a Russian speaking community in Dallas, who have been proven to be intelligence assets in the years since. It is one of these two that get Oswald his job at the TSBD building shortly before Kennedys visit to Dallas was scheduled. A warning about a potential assassination attempt planned in Miami in the weeks before was reported to the FBI by a person named "Lee".
Honestly I could list a million reasons why the official story is questionable at best and blatantly full of shit most of the time.
but what I think happened is this - JFK was killed by a small group of people within a specific covert ops group- because Kennedy wasn't complying with the plan to invade Cuba, avoided another conflict in Laos and then was working hard to keep Vietnam from escalating. In one of his last speeches, at American University, he made a drastic turn in his dialog about the USSR and essentially wasn't playing ball, so a sniper team that had been training for the invasion of Cuba and to assassinate Castro became furious with JFK, believed he was a threat to US security and believed his removal would not only be best for the country but also in interest of their industrialist financiers...
BUT - I really want to stress I don't know what happened or even feel solid about what I *think* happened.... but I believe anyone who really looks into that event objectively will find themselves staring into an abyss of deception.