You can start the process by filling out this questionnaire. http://www.atg.state.vt.us/assets/files/Employment%20Discrimination%20Complaint%20Form.pdf
This will help to get the ball rolling, as their are statute of limitation issues which may affect your case. For an overview of the process as a whole, check out http://www.atg.state.vt.us/issues/discrimination/civil-rights-unit-investigatory-process.php
Good answer above. Also check: https://egov.eeoc.gov/eas/ to see if the Equal Opportunity Employment Commission is the right agency. It is a federal agency. If your employer had more than 15 full-time employees, the feds will probably have jurisdiction. Make sure any charge is cross-filed between state and federal agencies.