To install the Max package, just unzip the downloaded file and copy the orchidea folder inside the Max folder located in your Documents folder. Some tutorials included in the package require the latest version Bach and Dada libraries to function properly, that you can find in the Max package manager.
To remove from MacOS quarantine the whole package at once, type:
xattr -rd com.apple.quarantine ~/Documents/Max\ 8/Packages/orchidea/*
The standalone version is still in pre-release; you need to download the datasets separately.
Command line tools
Download the command line version if you plan to do batch processing for research purposes; you need to download datasets separately.