Double-click Imagenomic-Portraiture-for-Lightroom-4.1.0.3-4103.dmg . A new volume will appear on your desktop and in Finder.
Ensure Adobe Lightroom Classic or Lightroom CC is completely shut down.
If you own a license, upgrading to this version is highly recommended for speed and stability. If you found this file on a torrent site, delete it immediately and download the official trial from Imagenomic to protect your Mac and your work.