A 64-bit version of 3ds Max is required.
Download Indigo for your system here; if you are unsure about which version to download, please see this tutorial page.
Upon running the installer, ensure that the "3ds Max plugin" component is selected for installation:
Continue with the normal install process for Indigo, after which the Indigo for 3ds Max installer will launch.
When the Indigo for 3ds Max installer launches, you will be prompted for the versions of 3ds Max you would like to use with Indigo:
If you encounter any problems installing Indigo for 3ds Max, please email us at support@indigorenderer.com.
After the Indigo for 3ds Max installer has completed, restart 3ds Max. Enter the Render Setup dialog by pressing F10, and click the "..." button next to the Production renderer entry in the Assign Renderer roll-out:
From the list of renderers, select "Indigo Renderer" :
Indigo for 3ds Max is now installed and ready to use.