Complex sentence: Lazarević started his coaching career at the age of 21, joining Car Konstantin as an Assistant coach in 2008, leaving in 2009 for a similar role at Radnički Niš until 2010.
Split into simpler sentences: Lazarević started his coaching career at the age of 21. Joining Car Konstantin as an Assistant coach in 2008, leaving in 2009 for a similar role at Radnički Niš until 2010.