Complex sentence: President Byun is an owner of a practice music studio that used by'Entertainer Band/tantara band' located in Hongdae, he used to work at KTOP and was a work-mate of KTOP CEO.
Split into simpler sentences: President Byun is the owner of a music rehearsing studio that is used by'Entertainer Band/tantara band' located in Hongdae. He used to work at KTOP and was a work-mate of KTOP CEO.