Complex sentence: He then briefly studied architecture at Regent Street Polytechnic before embarking studies in 1964 at the Chelsea School of Art for four years, before leaving with a scholarship, that took him on his first visit to the United States, in 1968.
Split into simpler sentences: He then briefly studied architecture at Regent Street Polytechnic before embarking studies in 1964 at the Chelsea School of Art for four yeard. He left with a scholarship, that took him on his first visit to the United States, in 1968.