Recommended installation method: use your package manager of choice to install Node Version Manager (the package is typically called "nvm").
For example:
brew install nvm
Then install node's (and npm's) latest version:
nvm install node
Export the postman collection and environment to files in the Postman directory inside your user home directory, for example:
%home%/Postman/myCollection.postman_collection.json and %home%/Postman/myEnv.postman_environment.json
Go to the root of this repo and enter:
node index.js myCollection myEnv
The HTML report will be generated inside the newman subfolder of this repo.