Nouns are people, places, things, and ideas. In German, nouns are ALWAYS capitalized.
All singular German nouns have one of three genders, indicated by the article that precedes it: the article der for masculine nouns, die for feminine, or das for neuter (If you're familiar with Spanish, it's just like the masculine 'el' and feminine 'la.').
Certain nouns always have a gender that you'd expect- for example, 'the man' is translated into 'der Mann,' using the masculine article.
Unfortunately, most other nouns have seemingly random articles. The only way to really know for sure which gender a noun has is to learn and memorize it.
There are a few tricks for certain nouns to recognize which gender it has. This was extremely helpful for me, and I recommend for you to memorize as many of these following rules as you can.
The German language is famous around the world for its super long words ("Donaudampfschifffahrtselektrizitätenhauptbetriebswerkbauunterbeamtengesellschaft," anyone?). In German, it is possible to form a 'compound noun,' or a noun formed by combining two or more nouns.
The purpose of this is to describe the last German word in the compound noun. In other words, the noun(s) that come before the last noun in the word become adjectives for the last.
Plurals are a bit tricky. The best way to learn plurals is to learn the plural form when learning the singular form for each noun. A few rules of plurals are listed below.
Relative clause refers to and further describes the preceding noun in the preceding clause. The relative clause refers to the noun with the relative pronouns which is chosen with case and gender of the preceding noun to which it refers.