Complex sentence: The protest in Ann Arbor, Michigan, which was organized by the group Stop Trump Ann Arbor, drew an estimated 100--150 demonstrators, who gathered at The Diag on the University of Michigan campus and marched to Liberty Plaza.
Split into simpler sentences: The protest in Ann Arbor, Michigan was organized by the group Stop Trump Ann Arbor, and drew an estimated 100--150 demonstrators. They gathered at The Diag on the University of Michigan campus and marched to Liberty Plaza.