Complex sentence: He then went onto work in several recording studios as an Audio Engineer/Session Drummer, it was at one recording studio that he met Stereophonics whilst they were recording their fourth studio album for which he played percussion.
Split into simpler sentences: He then went on to work in several recording studios as an Audio Engineer/Session Drummer. It was at one recording studio that he met Stereophonics whilst they were recording their fourth studio album for which he played percussion.