Complex sentence: The cops were already positioned at the Embassy when the marchers arrived, but the activists wanted to avoid a confrontation with the police and proceeded to Mendiola, where they made bonfires in the middle of the road.
Split into simpler sentences: The cops were positioned already when the march arrived at the Embassy, but the activists wanted to avoid a confrontation with the police and proceeded to Mendiola. There they made bonfires in the middle of the road.