I am interested in starting a union at work, details inside.

Our working conditions sort of suck and we have over 400 employees. They treat most everyone like cattle and the management is horrible. What steps do I need to take to get this going? How do I avoid getting fired while doing this?
We are a food and beverage company that handles all the food and liquor, beer, soda and snacks for a professional game arena. The company owns 23 arenas so this potentially could become huge.
I want to improve the cleanliness of the environment, stop favoritism, improve the system that is in place and allow for training to management which they currently do not have. I also would like to change some of the guidelines that are in place and provide benefits for employees at a discount.