Installing Maya and Arnold
Download the installers here:
Maya 2016 Installer – WIN (Direct download link, 1 GB)
Maya 2016 Service Pack 5 Installer (Update your Maya installation)
Arnold Renderer (Render Engine, free demo download)
After installation activate the Arnold plugin with the Plugin Manager in Maya:
Tick both mtoa.mll boxes, refresh, close.
Click the Render Settings Icon on the toolshelf
Select Arnold Renderer and change all Gamma Correction values to one. A value of one tells Maya to work internally with unchanged RAW color values. This is important to avoid over- or underexposed output.