For a more in depth look at the Israeli 9-11 attack it is recommended that you read Christopher Bollyn's book Solving 9-11: The Deception that Changed the World. Another similar exposay of the Jews who perpetrated this dastardly act can be read here. Or, if you are not a fan of long reading, watch 9-11 Missing Links.
Figuring out exactly how 9/11 was done is the work of crime investigators or conspiracy hobbyists who will endlessly go on discussing and debating every minuscule and intricate detail of the event to no avail. It doesn't take a structural engineer to tell you that two 110 story buildings and a 47 story steel skyscraper plummeting to the ground at nearly free-fall speed requires the assistance of explosives. All you need is two eyes that can see and a brain that thinks to come to that sound conclusion. This is why it is of my opinion that more emphasis should be placed on the "who" instead of the "how". It should be obvious to anyone that discovering 'who did 9/11' is infinitely more important than discovering how they did it.