How do you form the perfect tense?

The perfect tense is formed using the present tense form of the verb 'haber' for that subject followed by the past participle of the verb.

The conjugations of 'haber' are: yo 'he'; tu 'has';él/ella/Vd. 'ha'; nosotros 'hemos'; vosotros 'habéis'; ellos/ellas/Vds 'han'.

For example 'He has eaten' is translated as 'Ha comido' in Spanish. 'You have all arrived' is 'habéis llegado'.