Immigration is entering a country where you are not a native to take up permanent residence. Emigration is leaving a country where you have been a citizen.
Prepare a census timeline before you begin. Review what you will find in the census you are searching. Work backwards from the most recent census. Expect spelling and age variations.
To find a birth date from a death date, subtract the age in years, months and days from the date of death. This is a very close approximation.