The present tense indicates an action that is either recurring, habitual, or a general truth, a so-called eternal verity.
Siempre tenemos un Mexican Thanksgiving, que tiene que haber nachos, y tiene que haber frijoles, eso es muy traditional para nosotros.We always have a Mexican Thanksgiving, where you must have nachos, you must have beans, this is very traditional for us.
There are 4 main types of irregular verbs in the present tense: stem changers, irregulars in the yo form, irregular in all forms, spelling changers.
There are three types of stem changers: e-> ie, e-> i, o-> ue
Irregular in the yo form
decir, venir, hacer, tener
dar, saber, caber
Irregular in all forms
ser, ir, estar, oler
g > j: Verbs whose infinitive form ends in -gir change the g to j before an a or an o.
gu > g: Verbs whose infinitive form ends in -guir drop the u before an a or an o.