Accessing Filters

To create, edit, delete, rename, or set another default filter:
  Click the "Filters" button on the filter bar (fastest method).
Or use the menu "Newsgroup - Define Display Filter"

The buttons on the right side should be self-explanatory. Note that the default filter (in this case, Unread Articles) has a different icon.
To Create a filter, select "New…"
To set another filter as default, click the "Default" Button.
The copy button will create a copy of the selected filter, which you can then edit. This can save some work and time if the filter is complex or similar to another.
Ø    To re-name a filter, use Edit