Flash Games making is very challenging , ennoying, but at last- rewarding task.
I started off in FLASHKIT.com tutorials. just go to tutorials, and section about games.
They got whole bunch of stuff from click and drag to simple platformers.
When I was doing my Robotnik Duels game (can find it on Newgrounds in SONIC SPOOFS),
I was referring to flashkit.com for movement script. I got it, changed it, modifeied it and VIOLA!
Once you get a script and play around with it you get some sence of what goes on.
Hope that was helpful!