For all the information you need to know about obtaining a green card and becoming a US citizen go to these links for information and downloadable forms.
Green Cards: https://www.uscis.gov/greencard
Here are phone numbers and links to agencies in the Grand Rapids area that help with these processes:
City Life Church Immigration Connection
Grand Rapids Community College Citizenship Classes
Phone: 616.234.3172 or 616.454.4874
Immigration Legal Services, Diocese of Grand Rapids
Justice for Our Neighbors (JFON)