How to manipulate movieclips from a class file?

Hi,

I don’t know how to manipulate/access movieclips from a class file. Is it possible? What i know is when you right click the movieclip from the library you can link in to your class. I want to know if i can do it without that method.

For example:

Main.fla - ** box1_mc, box2_mc, box3_mc**

MyClass.as - how can i set their alpha from this class? (box1_mc.alpha = 0, etc)… something like this

I’m new to making a class so any help is appreciated…Thanks