Chat command /fcoiss (press RETURN key afterwards)

Or Press ESC -> navigate to the settings page -> navigate to the addons page -> navigate to "FCO ItemSaver" or use the search icon at the top to search for "FCO" e.g..

Third possibility is to enable the FCOIS settings menu button at your main menu bar:

To enable this button open the AddOn settings -> FCOItemSaver -> Additional buttons -> and enable the FCOIS settings button in main menu setting.