Agreement in gender & number, placement in a sentences

As you have learned all nouns in French have a gender, not just those referring to people.

All words associated with the noun: articles, adjectives, possessive adjectives; must agree with the noun in gender and number.

What does this mean? Usually it means add an –e- to the end of the adjective if the noun is feminine & add an –s- or sometimes an –x-, if it is plural.