Complex sentence: In 1975 he was promoted to Brigadier and the position of General Officer Commanding (GOC) and in the folowing hear he became the Chief of Army Staff to the Head of State Olusegun Obasanjo.
Split into simpler sentences: In 1975 he was promoted to Brigadier and the position of General Officer Commanding (GOC). In 1976 he became the Chief of Army Staff to the Head of State Olusegun Obasanjo.