The most important symbol is given in the title of the book. A Red Badge of Courage is supposed to be a battle wound. Henry wishes for one, but when he finally is wounded, it is from being struck with a rifle butt by one of his own men. Henry lies about the source of the wound and, ironically, gains the confidence of the men in his regiment. Crane also uses many symbols from nature. For example, the many references to flowers represent how fragile and temporary life is. One other reference often referred to his the "wafer-sun". Henry sees this when he becomes aware that he really might die. It probably symbolizes a communion wafer at a church service. Two other symbolic use of names are also important. If you read through the book, we do not learn Henry's name until after he has gone through a battle. Until then, he is simply referred to as "the youth". This indicates that Crane does not think of the boy as worthy of a name until he has been tested by battle. The other symbolic name is that of Jim Conklin. His tragic death has a tremendous effect on Henry. The initials of Conklin's name (J.C.) suggest Jesus Christ and indicate that Conklin is a type of Christ-figure in the novel.
to start, letters and numbers, try to ask a question that is less broad, if you want soecific answers.