Get hold of a dictionary. If you do not have one at home, you can buy it from the local bookstore. Another option is to visit a library and use one of the dictionaries available there.
Look up nouns in the dictionary, starting from the letter "A." The dictionary lists English words along with their meanings in the alphabetic order, from A to Z. It also states whether a word is a noun, verb, adjective or other. Simply go down the list for the letter "A" and look up the description for the first few words. Look for the italicized "n" or "noun" next to the word. This will show that the word is a noun.
Repeat the procedure for all letters of the alphabet, until you find a noun for every letter.