Working with functions in external as file

Hello …

Im trying to understand alittle more about using external files.

In my flash actionscript window i basicly want to access a function that i wish to put in an external .as file … but i just cant seem to get it…

like:

myFunction();

in external file

function myFunction() {
   trace("test");
}

I’v been trying some code but it dont work very well…
(myClass.as)

package {
   public class myClass{
      public function myClass() {
         trace("test");
      }
   }
}

and in my flash file the only way for it to trace was if i wrote:

var test:myClass = new myClass();

But i dont get it … how can i access the function form wherever i want … so i basicly can type myClass() and it traces again … i dont wanna create variables to run the functions … i hope you understand and i hope/suppose its probably very basic…

I prolly got it all wrong… i’v tryd to figure out if i can/should access it with import instead… but dident get that to work either…