1. Display the palette menu and select from the list the "Production" set (movie). The new actions appear under the default set.

2. Again, open the palette menu and choose "Load Actions". It opens a standard system filebox. Find on your computer any other actions set* (an .atn file) and load it.
*In the movie, I load from C:\Program Files\Adobe\Photoshop CS\Presets\Photoshop Actions

3. There are too many actions in the palette now. To thin them out, let's switch to the list mode (movie).

4. From the palette menu, select the "New Set" command or click the "new set" button on the palette (movie). In the New Set dialog, type the set name, for example "My Actions", and click OK.

5. Drag the "Fit Image" action from the "Production" set, and drop it onto the "My Actions". Then add several other useful (in your opinion) actions.

6. To discard the unnecessary stuff, just drag it onto the "trash" button (movie).

NB Don't be afraid of "spoiling" the pre-packaged actions. You always can re-load them or restore the default set.