Part 1. Noun phrases

Like in English, Spanish noun phrases consist of (minimally) a noun and an article.
Compare:         the dog         el perro

Also like in English, the Spanish articles can be definite or indefinite.
Compare:         definite         the dog         el perro
                            indefinite      a dog             un perro

Unfortunately, Spanish articles also encode two concepts which are not encoded in English articles. They are number and gender. Number, like in English refers to "singular" (or one thing) and "plural" (or more than one thing). We have this concept, it's just not expressed in the English article.

                                                singular                                   plural
Compare:         definite         el perro     the dog             los perros         the dogs
                            indefinite      un perro     a dog                unos perros     some dogs

The final category that must be expressed in noun phrases is called "gender". Gender in Spanish is totally different from gender in English, so pay attention! "Gender" is a noun classification system. All nouns in Spanish are arbitrarily called either "masculine" or "feminine". It so happens that for people (and some animals) in Spanish, grammatical gender coincides with biological sex. For example, 'el hombre', 'la mujer', el/la muchacho/a, el perro, la perra. However, there are lots of nouns which are not alive (like tables and chairs and walls and pencils) which are arbitrarily called either "masculine" or "feminine". You will have to learn the gender of each noun.

HERE is the final incorporation of GENDER into our NOUN PHRASE chart:

                                                         singular                                 plural

MASCULINE     definite         el perro         the dog           los perros         the dogs
                                  indefinite     un perro         a dog              unos perros     some dogs

FEMINIINE         definite         la mesa         the table         las mesas         the tables
                                    indefinite     una mesa     a table             unas mesas     some tables
 

Part 2. Adjective placement.

Adjectives are words that describe nouns, like:

                ill     healthy     big     tiny     crazy     silly

We can incorporate adjectives into our noun phrase from Part 1. In English, adjectives go before the noun that they describe (but after the article), and there's nothing else to consider:

the big tomato
the delicious fish

In Spanish, adjectives go AFTER the noun they describe, and we have to consider gender and number, too. The adjective must be marked with the same GENDER and NUMBER as the noun which it describes. (In the list of adjectives below, "bien" and "grande" are the only adjectives which do not have an overt gender marker; all the others can be marked masculine or feminine. All can be marked for plural.)

el tomate grande
el pescado sabroso

los tomates grandes
los pescados sabrosos

la flor bonita
las flores bonitas
una flor bonita
unas flores bonitas

Here are some new vocabulary words:

Adjectives:                                     Nouns:

grande             large                         el campo             countryside
pequeño/a       small                         el/la primo/a     cousin
tonto/a             foolish                     el coche                 car
perezoso/a       lazy                         el día                     day
tranquilo/a         quiet, peaceful     el verano             summer
perfecto/a          perfect                     la primavera     spring
bien                     well                         el otoño                 autumn
bueno/a             good                         el invierno             winter
malo/a                 bad                         la flor                     flower
hermoso/a         beautiful
bonito/a             pretty
feo/a                     ugly
 

Part 3. Spanish pronouns

Learn these pronouns according to person and number (and note the gender):

person                 singular                                     plural
1                            I                           yo                 we                                 nosotros
2                            you (informal) tú                   y'all                               vosotros
3                             you (formal)     Usted         you (plural formal)     Ustedes
                                he                         él                they (men or mixed)     ellos
                                she                         ella           they (all female)             ellas