npm install
SESSION_SECRET='any arbitrary secret' development=true npm start
The site will be accessible at http://localhost:80
For full functionality, you will also need to set up a Sendgrid account and a Recaptcha account that serves localhost or your own domain. In this case, you would start the server like so:
SENDGRID_API_KEY='your sendgrid API key' SESSION_SECRET='any arbitrary secret' RECAPTCHA_SECRET='your recaptcha secret' development=true npm start