In nodeMailer, where is the transport object created

This is a simple question. I have an app created using Node.JS. I am trying to follow the instructions at nodeMailer to create a mailer to use for a contact form in my index.html file. I have already installed nodemailer into my node_modules folder ($npm install nodemailer --save) and I am using Node.JS v6.10. The instructions then say to "create a transport object" and gives a sample of the transport object code. Where (specifically, in what file) do I create this transport object (in other words, where does this code go?)? Or do I create a new file (and if so, under what folder)? Below is a screenshot of my app directory. Can someone point me to where I am suppose to place the code for the transport object?

via jcbridwe