can you pleas explain this quote more and give me a description on Walter, "while walter piled food on his plate, he and atticus talked together like two men, to the wonderment of jem and me...... atticus was expounding upon farm problems when walter

Atticus treats Walter with respect and speaks to him in an adult fashion. They discuss farming, something neither of his own children understand, and Walter explains to Atticus how helping his father with the crops keeps him out of school.

Atticus greeted Walter and began a discussion about crops neither Jem nor I could follow. “Reason I can’t pass the first grade, Mr. Finch, is I’ve had to stay out ever‘ spring an’ help Papa with the choppin‘, but there’s another’n at the house now that’s field size.” While Walter piled food on his plate, he and Atticus talked together like two men...

Walter simply just did not get to eat at home so lunch at The Finch home would have been a feast.