Complex sentence: Brown began his performing career at the age of 12, forming his first vocal group, the Cremona Trio in 1945, where they won local talent shows at Augusta concert halls such as the Lenox and Harlem theaters.
Split into simpler sentences: Brown began his performing career at age 12, forming his first vocal group, the Cremona Trio in 1945. That same year they won local talent shows at Augusta concert halls such as the Lenox and Harlem theaters.