Complex sentence: She wakes up in a concrete room chained to a wall, and is approached by a man named Howard, who explains that an unknown attack has taken place and that he brought her to his bunker after finding her on the side of the road.
Split into simpler sentences: She wakes up in a concrete room chained to a wall, attended to by a man named Howard. He explains that an unknown attack has taken place and that he brought her to his bunker after finding her on the side of the road.