There are three types of conjugations in Spanish and we recognised them looking at the  infinitive ending:

1st conjugation: -ar     Examples: comprar, bajar, limpiar, trabajar….
2nd conjugation: -er    Examples: aprender, beber, correr, vender….
3rd conjugation: -ir      Examples: recibir, abrir, subir, vivir, repartir….

When we want to conjugate a verb in any of  its  tenses  we take the conjugation ending (ar,er,ir) and we add to the “root” of the verb the corresponding ending of the person doing the verb action.
There are three persons for the singular and three persons for the plural:

Singular
I – Yo
You – Tú
He – Él, She – Ella. There is no “it” in Spanish, you refer to things in masculine or feminine.
Plural
We – Nosotros, nosotras
You – Vosotros, vosotras
They – Ellos, ellas.

It’s very important to know the endings of the verbs because most of the time we omit  the subject pronom in Spanish so, by knowing the endings, you will be able to tell what person is doing the action and in what tense is the action taking place (present, past, future).

Depending on the attitude of the person doing the action, the Spanish verbs are structured in different moods. The most common one is the Indicative, but there are three more subjunctive, conditional and imperative.

Spanish Verb tenses:
INDICATIVE MOOD

Simple tenses

Present –  Present simple
Imperfect – Pretérito imperfecto.
Preterit – Pretérito perfecto simple o indefinido.
Future –  Futuro.
Conditional – Condicional.
Compound tenses

Present perfect – Pretérito perfecto compuesto.
Pluperfect – Pretérito pluscuamperfecto.
Preterit Perfect – Pretérito anterior.
Future Perfect – Futuro perfecto.
Conditional Perfect – Condicional compuesto.
SUBJUNCTIVE MOOD

Present – Present simple.

Imperfect – Pretérito imperfecto.

Present perfect – Pretérito perfecto compuesto.
Pluperfect – Pretérito pluscuamperfecto.