QuikFynd software is typically available for direct download from your NAS. But you may also download it from links available on this page for your particular NAS model
WDMyCloud NAS systems
QuikFynd is currently available for WDMyCloud series of NAS systems. You may install QuikFynd search server as an App via the WD NAS management console. After installation, QuikFynd search server will start automatically. Initial setup is a breeze and here is a the link to Getting Started guide. If you are not able to find QuikFynd for download in WD NAS console, you may download it from following links.
WDMyCloud Mirror (2nd Generation)
WDMyCloud Mirror (1st Generation)