Complex sentence: In the summer of 1987, Kim Gwang-seok and other student musicians he affiliated with recorded some practice pieces, which drew attention of Kim Chang Wan, the frontman of the rock band San Ul Lim, a major figure in Korean popular music.
Split into simpler sentences: In the summer of 1987, Kim Gwang-seok and other student musicians he affiliated with recorded some practice pieces. This drew the attention of Kim Chang Wan, the frontman of the rock band San Ul Lim, a major figure in Korean popular music.