Hey Omar Welcome to the forum, I hope you enjoy it as much as we do.
As Terry said the easiest is probably a rear rack mount type, but we have had a few members mount the motor in frame (so to speak).
Our great member SilverBear has this build http://motorbicycling.com/f38/39-elg...hed-17682.html
Yeah it's a little different as far as frame wise but will give you an idea of what is possible.
And here is a photo of another bike