Flash MX 2004 - loading within a screen

Help me! When I click on a button in a screen, I want it to load in a designated area within a screen.

Do I create another flash file and link it to the spot in the screen to load to acheive this effect? or do I make it within the designated area? How do I link the file to load in the screen or make it within the area depending on the answer?

thanks guys, ahead of time!