How do I form the present perfect tense?

To form the present perfect tense we combine the AUXILLARY VERB (conjugated in the present tense) with the PAST PARTICIPLE

EXAMPLE: I have watched, you have studied, he has been

Auxilliary verb = haber = he, has, ha, hemos, habéis, han 

Past participle AR stem -ado -ido 

EXAMPLE = comer ..... comer ..... comido

(yo) he comido

(tú) has comido 

(él/ella/usted) ha comido

(nosotros/as) hemos comido

(vosotros/as) habéis comido

(ellos/as/ustedes) han comido