Drop the 'RNZAF-****' Folders included in this 'RAR' compressed file into your DCS installation \CoreMods\aircraft\FA-18C\Liveries\FA-18C_hornet folder. This will not replace any other files or folders.

To uninstall, simply go to your DCS installation \CoreMods\aircraft\FA-18C\Liveries\FA-18C_hornet folder and delete the folders called 'RNZAF-****'.