Complex sentence: At the end of the campaign he returned to Portugal, joining Boavista FC; he contributed with eight substitute appearances in his first year, as the "Chequereds" won their first and only national championship.
Split into simpler sentences: At the end of the campaign he returned to Portugal, joining Boavista FC. He contributed with eight substitute appearances in his first year, as the "Chequereds" won their first and only national championship.