Complex sentence: Merxat began his career as a fashion model at age 22, when he attended the Asian Sportsman Contest and came into the top 10, and signed with the agency Yu Zheng Studio.
Split into simpler sentences: Merxat began his career as a fashion model at age 22, when he entered the Asian Sportsman Contest and emerged as the top 10. Following which, he signed with the agency Yu Zheng Studio.