I am trying to get my father in law back to the us but don't know where to start. He was deported 5 or6 years ago and has a ssn

Your father-in-law may be able to return depending upon why he was removed from the country. Not everyone removed from the country can return. Assuming your father-in-law could return, the first step would be to have a spouse, son or daughter, parent, or sibling file an immigrant visa petition on his behalf. He may require a waiver to return. Most waivers are based on extreme hardship to a qualifying relative. You can read more about family immigration at http://myattorneyusa.com/adjustment-of-immigration-status.