The past participles of verbs are often used as adjectives. So they agree in number and gender with the noun they modify, just like regular adjectives. Adjectives derived from past participles are similar to -ed adjectives in English: cocido (cooked), confundido (confused), preparado (prepared). Past participle formation depends on the verb class (–ar, -er, -ir, or irregular). –ado is the past participle ending used for regular –ar verbs, while –ido is used for –er and –ir verbs.
Las tradiciones de estar sentados en la mesa juntos como familia para comer.The tradition of sitting together at the table as a family to eat. Llegó todo quemado del sol de siete días. Y llegó todo sucio.
He arrived all burnt from 7 days in the sun. And he arrived completely dirty.