How were the Jews supposed to gather the firstfruits sheaf?
The Jews were to go into a green barley field and pluck the early ripened stems with their heads, gathering enough for a sheaf of firstfruits to bring to the priest as a wave offering. They took only the early-ripening grain, not the whole harvest.
Les explains that barley was the first grain harvested in the spring. In a field still green and headed out, scattered yellow heads of grain would ripen early before the mass of the surrounding stems. The Jews were to go into that green field and pluck those early-ripened stems with the heads, enough to make a sheaf. Then they would take it to the priest, and it was a wave offering. When they came into the land and reaped the harvest, they were to bring the firstfruits to the priest.