To get started, install the emailizer module. I recommend installing it globally so you can simply call it from anywhere and watch a specific folder:
npm install emailizer -g
You can also use emailizer as a framework to start a basic email template (this will create a folder called NAME in the current directory and copy a sample email - based on Ink, and open an http server to show the email in the browser):
emailizer create NAME
You can then use emailizer to watch an html email which has its CSS linked in the head and auto-render to an output folder:
emailizer watch ./SOURCE ./DEST
Note: You can use both relative and absolute paths.