Complex sentence: At the age of 17 he started a management company with friends Les Horne and Fran Adamson and raised enough money to record an album and shopped it in the U.S., immediately garnering the attention of CBS which offered him a deal.
Split into simpler sentences: At the age of 17 he started a management company with friends Les Horne and Fran Adamson, and raised enough money to record an album and began shopping it to the U.S. market. It immediately garnered the attention of CBS which offered him a deal.