In Spanish, regular -ir verbs have different endings when we use them in the present tense. Here’s an easy guide to these endings:

• Yo: -o (for example, vivir → vivo)
• Tú: -es (for example, vivir → vives)
• Él/Ella/Usted: -e (for example, vivir → vive)
• Nosotros/Nosotras: -imos (for example, vivir → vivimos)
• Vosotros/Vosotras: -ís (for example, vivir → vivís)
• Ellos/Ellas/Ustedes: -en (for example, vivir → viven)

Just remember, some verbs are irregular, which means they don’t follow these rules. For example, ser (soy), estar (estoy), and ir (voy) are irregular verbs.

Now let’s talk about adjectives. They need to match with nouns in gender and number. This means:

• For one item, you might use "el" or "la", like "el libro rojo" (the red book).
• For more than one item, you’d say "los libros rojos" (the red books).

The words "el" and "la" are called definite articles. They point to something specific. On the other hand, "un" and "una" are indefinite articles. They refer to something more general.

Next, let’s look at the simple past tense for regular -ir verbs. Here are the endings you need:

• Yo: -í (for example, vivir → viví)
• Tú: -iste (for example, vivir → viviste)
• Él/Ella/Usted: -ió (for example, vivir → vivió)
• Nosotros/Nosotras: -imos (for example, vivir → vivimos)
• Vosotros/Vosotras: -isteis (for example, vivir → vivisteis)
• Ellos/Ellas/Ustedes: -ieron (for example, vivir → vivieron)

With these endings, you can start making sentences in both present and simple past tense!