From the manual page 71.
Saving and Using Custom Column Layouts
You can create customized column layouts and save them for easy access at any time.
To save a custom column layout:
1 Rearrange the Browser columns the way you want them to appear.
Note: The Name column always appears on the far left and cannot be moved.
2 Control-click any column heading, then choose Save Column Layout from the
shortcut menu.
3 In the Save dialog, choose where you want to save the layout, change its name if you like, then click Save.
Custom column layout files are saved by default to the following folder location:
/Users/username/Library/Preferences/Final Cut Pro User Data/Column Layouts/
To open a custom column layout:
Control-click any column heading in the Browser except Name, then choose a custom layout from the shortcut menu.
If you have placed column layouts in a location other than the default folder mentioned above, you will need to open them using the Load Column Layout command in the shortcut menu.
To open a custom column layout that is not in the default location:
1 Control-click any column heading in the Browser except Name, then choose Load Column Layout from the shortcut menu.
2 In the Choose a File dialog, navigate to the location where the column layout is stored, select it, then click Choose.
Tip: You can also save and use custom column layouts in the Find Results window, following the same instructions you use for the Browser. Any custom column layouts created in the Browser can be used in the Find Results window, and vice versa.