Where to put add on attribute controller?

I download the add on attribute controller that will allow you to select more than one value at a time and will only show values in a selected name. But I cannot find where to place it in my files so it will work. Could anyone point me to where to install this so it will work?
Thanks,
Tasha

What I suggest is that you find and rename /admin/attributes_controller.php to admin_controller.orig

Then replace it with the module file in the same location /admin

Then if you follow this convention for all core files that can not be overriden, when you do an upgrade you can first locate all the files that you have changed and make copies so that you do not lose the functionality they provide and also compare them to the new files