Verbs are critical components in sentence construction. The verb indicates action or movement. When conjugating Spanish verbs there are six positions: three singular and three plural. Vosotros (omitted here) is the second person plural and rarely used in North America. Whether regular or irregular, verb endings are a, e and i, as in the words tomar (to take), comer (to eat), and vivir (to live). Here, verbs are conjugated from the infinitive form to the past/preterite tense in the indicative because the indicative relates what is real.
There are three conjugations in Spanish: ar, er, ir
The six positions for conjugating verbs are: Yo (I), Usted/tú (you, formal/informal), ella/el/ (she, he, it), nosotros (we), ellas/ellos/ustedes (they/them).
There are three major conjugations indicated by the vowels a, e, i, and followed by the consonant r. The first form of the three verbs--those ending in "ar"--are conjugated into the preterite by dropping the ending "ar" (i.e. tomar, tom-ar = tom). You are left with the root of the word. Add to the root the following endings corresponding to the persons (yo, tu, el/ella, nosotros, ustedes) -é, -aste, -ó, -amos, -aron.
The second main conjugation is the ending "er," as in the verb comer. Drop the ending, er. Take the root of the word which is com and add endings -í, -iste, -ió, -imos, -ieron. Thus the conjugation of the Spanish word for comer (to eat): yo comí, tú comiste, él/usted comió, nosotros comimos, ellos/ustedes comieron.
Vivir (to live) ends in ir, the third of the main conjugations. Following the pattern, you would drop the "ir" to form the root "viv" and add -í, -iste, -ió, -imos or -ieron. Vivir (to live): yo viví, tú viviste, él/usted vivió, nosotros vivimos, ellos/ustedes vivieron. Note that the verbs ending in er and ir have the same endings.
Learning to conjugate and distinguish between regular and irregular verbs takes lots of practice each day.
Try not to get discouraged. Many differences exist between Spanish and English grammar. A good tutor can augment your progress toward mastering verb conjugations.