Platforming - Within a .fla


Does anyone have any information regarding tutorials or just a brief outline of what is needed when making a platformer style game within Actionscript 3? The caveat is that I’d much rather keep all code within a .fla rather than have a million classes; I’m only starting out with AS3.

I understand the maths behind the movement, however I am struggling to figure out how to code a movie clip to collide with another, or how to make the jump work properly. Does anyone have any example code/tutorials etc?

Thank you!