Complex sentence: To the far end is the High Table, placed on a platform a step above ground level, where fellows and their guests dine; in front of it are three long benches where students dine, set perpendicular to the High Table and spanning to the entrance.
Split into simpler sentences: To the far end of the hall is the High Table, placed on a platform one step above ground level, where fellows and their guests dine. Students dine at three long benches in front of and perpendicular to the High Table and spanning to the entrance.