The two most essential German verbs are "sein" (to be) and "haben" (to have), and both are irregular. In the present tense, "sein" conjugates as ich bin, du bist, er/sie/es ist, then wir sind, ihr seid, sie/Sie sind. The verb "haben" follows a similar irregular pattern: ich habe, du hast, er/sie/es hat, wir haben, ihr habt, sie/Sie haben. These two verbs will appear again and again in compound tenses, so memorizing them early pays off.
A regular verb like "gehen" (to go) follows the more predictable pattern of adding typical personal endings: ich gehe, du gehst, er geht. Other verbs are stem-changing, meaning the vowel in their stem changes in the du and er/sie/es forms but not in the ich form. For example, "sprechen" (to speak) switches its stem vowel from e to i in those forms: ich spreche, du sprichst, er spricht. Similarly, "fahren" (to drive) changes a to ä: ich fahre, du fährst, er fährt. Recognizing these patterns helps you conjugate new verbs as you encounter them.
Negating in German can take two forms, depending on what you want to negate. To negate a verb in general, place "nicht" after the verb or in front of the specific element being negated; for example, "Ich spreche nicht" means "I am not speaking." When negating a noun that would otherwise carry an indefinite article, use "kein" (for masculine or neuter) or "keine" (for feminine or plural) instead of "nicht ein." So "Ich habe keine Zeit" translates as "I have no time," not "I don't have a time."