Complex sentence: Mark arranges with Vivian (Moira Shearer), a stand-in at the studio, to make a film after the set is closed; he then kills her and stuffs her into a prop trunk.
Split into simpler sentences: Mark arranges with Vivian (Moira Shearer), a stand-in at the studio, to make a film after the set is closed. He kills her and stuffs her into a prop trunk.