Complex sentence: It made its radio premier a day later on KIIS-FM's "On Air With Ryan Seacrest" before being sent for radio adds on December 8,2009 and digital download on December 21,2009 in the United States and Canada.
Split into simpler sentences: It made its radio premier a day later on KIIS-FM's "On Air With Ryan Seacrest" before being sent for radio adds on December 8,2009. It was then releases as a digital download on December 21,2009 in the United States and Canada.