Complex sentence: Upon subsequently finishing his high school at Narsee Monjee College of Commerce and Economics, he studied a Bachelor of Commerce at HR College, Mumbai, where at age 18 he began training himself as a dancer, much before he had delved into acting.
Split into simpler sentences: Upon subsequently finishing his high school at Narsee Monjee College of Commerce and Economics, he studied a Bachelor of Commerce at HR College, Mumbai. As an 18 year old studying at HR, he began training himself as a dancer, much before he had delved into acting.