Trial and Error.
Read as much as can. Practice. If it breaks, it breaks. It won’t hurt. Try again! This topic could also be called “key to success”. I prefer to say trial and error. It makes nerd stuff feel like rock ‘n roll.
Be nice.
All the time. This is real life.
Write a Flash-Video Player (Actionscript 3)
Be sure to check out NetConnection, NetStream (both dispatch NetStatusEvents) and Video.
...
Which Operating System?
I recommend Linux & Windows. In this order. Be aware of apples.