Variable help

I’m creating a dynamic movieclip and the name/instance name is stored in a variable. How can I reference the instance if its stored in a variable?

This is what I’m using and it doesnt seem to work (for obvious reasons). I know in php that you do this “blah blah” . $variable . “blah blah”;

Do I need to do something like that here?;

Any help would be greatly appreciated!