Grammatical Overview: Noun Properties
A noun is a name (nomen) given to a person, place, or thing. Nouns have the following properties: 1) gender, 2) number, 3) person, and 4) case.
Gender is a property that indicates the sex of the referrent (masculine or feminine). In Hebrew, however, the correlation between the gender of a noun and its referrent is generally accidental. For example, the word Torah in Hebrew is feminine, but that does not imply anything about the nature of the Torah itself. Unlike Greek, there is no "neuter" gender in Hebrew.
Number is the property that indicates whether one or more than one object is referenced when using the word. Hebrew has singular nouns (one object), plural nouns (more than one object), and dual nouns (a pair of objects). For plural nouns, there are regular plurals, irregular plurals, dual plurals, and plurals functioning as singular nouns.
Person refers to the relationship between the noun and the speaker. A noun can be in the first person (I, John, am here), second person (Oh, John!), or third person (John is here). Normally these distinctions apply to the study of pronouns, but they are implicit in the grammar of the noun as well.
Case indicates the grammatical function of the noun in a sentence. The noun can be a subject of a sentence (Hebrew is fun), an object in a sentence (John loves Hebrew), or in a possessive relationship with an object (John's Hebrew book). For possessives, Hebrew uses a "construct state" where one of two (or more) Hebrew nouns appear as a chain in a sentence (more later).
In general Hebrew uses endings to indicate these various properties of nouns. By learning the root of the noun and its endings, you will begin to understand the way nouns function in Hebrew sentences.
Study Tip: When first learning a noun, I recommend writing out a flash card with the gender, singular form, plural form and construct form on the front, and the definition on the back. You might also want to include a sentence that uses the noun in your definition.
Buying a Hebrew Dictionary: At this point in your studies, you should buy either a good Hebrew-English dictionary or use a Biblical Hebrew word frequency list. I recommend the Langenscheidt's Pocket Dictionary for beginners.