Complex sentence: Flynt attended Salyersville High School (now Magoffin County High School) in the ninth grade, however ran away from home and, despite being only 15 years old, joined the United States Army using a counterfeit birth certificate.
Split into simpler sentences: Flynt attended Salyersville High School (now Magoffin County High School) in the ninth grade. However, he ran away from home and, despite being only 15 years old, joined the United States Army using a counterfeit birth certificate.