cannot attach applescript handler

I am trying to make my first application and I am stuck.
I am unable to attach a handler. The Action>>clicked is faded. See the picture.

I am using xcode 3


choose a script from the Script menu

Thanks, StefanK.

I was actually following an old video which used Xcode 2 or some version before Xcode 3

Video: Creating a AppleScript Application pt. 2

In the video, it looked like this:

Now, I understand that in Xcode 3, I have to edit the script in “Scripts” folder (which is above the “Resources” folder) and then select it when using “Interface Builder”.

sorry for this stupid question but i am tired of using the mouse and googling:

How to open the interface builder through mainmenu.xib with keyboard. I have found that double-clicking opens it but pressing return does not.