What was Ruth picking up in the field?

Ruth 2:2-23 GNBUK

One day Ruth said to Naomi, “Let me go to the fields to gather the corn that the harvest workers leave. I am sure to find someone who will let me work with him.” Naomi answered, “Go ahead, my daughter.” So Ruth went out to the fields and walked behind the workers, picking up the corn which they left. It so happened that she was in a field that belonged to Boaz. Some time later Boaz himself arrived from Bethlehem and greeted the workers. “The LORD be with you!” he said. “The LORD bless you!” they answered. Boaz asked the man in charge, “Who is that young woman?” The man answered, “She is the young woman from Moab who came back with Naomi. She asked me to let her follow the workers and pick up the corn. She has been working since early morning and has just now stopped to rest for a while under the shelter.” Then Boaz said to Ruth, “Let me give you some advice. Don't pick up corn anywhere except in this field. Work with the women here; watch them to see where they are reaping and stay with them. I have ordered my men not to molest you. And whenever you are thirsty, go and drink from the water jars that they have filled.” Ruth bowed down with her face touching the ground, and said to Boaz, “Why should you be so concerned about me? Why should you be so kind to a foreigner?” Boaz answered, “I have heard about everything that you have done for your mother-in-law since your husband died. I know how you left your father and mother and your own country and how you came to live among a people you had never known before. May the LORD reward you for what you have done. May you have a full reward from the LORD God of Israel, to whom you have come for protection!” Ruth answered, “You are very kind to me, sir. You have made me feel better by speaking gently to me, even though I am not the equal of one of your servants.” At mealtime Boaz said to Ruth, “Come and have a piece of bread, and dip it in the sauce.” So she sat with the workers, and Boaz passed some roasted grain to her. She ate until she was satisfied, and she still had some food left over. After she had left to go on picking up corn, Boaz ordered the workers, “Let her pick it up even where the bundles are lying, and don't say anything to stop her. Besides that, pull out some corn from the bundles and leave it for her to pick up.” So Ruth went on gathering corn in the field until evening, and when she had beaten it out, she found she had nearly ten kilogrammes. She took the corn back into town and showed her mother-in-law how much she had gathered. She also gave her the food left over from the meal. Naomi asked her, “Where did you gather all this? Whose field have you been working in? May God bless the man who took an interest in you!” So Ruth told Naomi that she had been working in a field belonging to a man named Boaz. “May the LORD bless Boaz!” Naomi exclaimed. “The LORD always keeps his promises to the living and the dead.” And she went on, “That man is a close relative of ours, one of those responsible for taking care of us.” Then Ruth said, “Best of all, he told me to keep picking up corn with his workers until they finish the harvest.” Naomi said to Ruth, “Yes, my daughter, it will be better for you to work with the women in Boaz' field. You might be molested if you went to someone else's field.” So Ruth worked with them and gathered corn until all the barley and wheat had been harvested. And she continued to live with her mother-in-law.

GNBUK: Good News Bible (Anglicised) 1994

What was Ruth picking in the field?

What was Ruth doing in the field?

What was Ruth doing in the field of corn and barley?

Why does Ruth go to glean in the fields belonging to Boaz?