# Now it happened

This phrase is used here to mark the beginning of a new part of the story.

# grainfields

These are large sections of land where people had scattered wheat seed to grow wheat.

# heads of grain

These are the topmost parts of the grain plant, which is a kind of large grass. The heads hold the mature, edible seeds of the plant.

# rubbing them between their hands

"rubbing the husks off with their hands." They were rubbing off the outer husks so they could eat the seeds.