Complex sentence: When Vince Sr. asked him to manage the site of WWF's broadcasts, the Turner Arena in Washington, DC, Dudley became the first African-American to run a major arena in the United States.
Split into simpler sentences: When Vince Sr. asked Dudley to manage the site of WWF's broadcasts, the Turner Arena in Washington, DC, history was made. No other African-American had ever run a major arena in the United States.