Symbols In "A White Heron" and "The Yellow Wall-Paper"

For "A White Heron" I just picked the symbols we did in class: cow, milk, gun, white. I'm not exactly sure what most of these mean, I'm not too good with symbolism. For "The Yellow Wall-Paper" I picked: haunted house, yellow, wall-paper. Like before I'm not exactly sure how to spot out these symbols or what they mean. I'm hoping thursday's class will help me better understand this topic.