Overriding the Accessible content table layout

Hi,

I'm trying to override the layout of the table with the overview of Accessible Content, to add some functionality.

In the code of module_grants_monitor.pages.inc on line 148 there is a comment about overriding the default way in which the nodes summary is displayed. I would like to do so. But I don't understand the instruction on how to do that. I'm relatively new to Drupal.

I've created a module and I have this function copy-pasted in there. But how exactly do I register the theme_hook? Do I have to rename the function or anything?

From the code:
> If you do, don't forget to register this theme_hook() via _theme()
> in a manner similar to module_grants_module_theme()

Thanks for any help!
Bart