Complex sentence: He soon started helping lead protests by the organizations against civil rights infractions in Alabama; then in April 1965, went to Mississippi to help the Mississippi Freedom Democratic Party get black voters registered, where he worked with Unita Blackwell and Fannie Lou Hamer.
Split into simpler sentences: He soon started helping lead protests by the organizations against civil rights infractions in Alabama. Then, in April 1965, he went to Mississippi to help the Mississippi Freedom Democratic Party get black voters registered, where he worked with Unita Blackwell and Fannie Lou Hamer.