Complex sentence: Balbuena worked for AAA/Lucha Libre AAA Worldwide (AAA) since 1996, both as a wrestler and a trainer, having been involved in training almost all young wrestlers who worked for in that period of time.
Split into simpler sentences: Balbuena worked for AAA/Lucha Libre AAA Worldwide (AAA) since 1996, both as a wrestler and a trainer. He was involved in training almost all young wrestlers who worked for the promotion during that period of time.