To say what happened at a finished moment in the past, drop the infinitive ending and add the perfeito endings: -ar verbs take -ei, -aste, -ou, -ámos, -aram; -er verbs take -i, -este, -eu, -emos, -eram; -ir verbs take -i, -iste, -iu, -imos, -iram. Use it for completed, bounded events (ontem, no sábado passado, há dois anos), not for what you used to do.
Examples
- Ontem falei com a minha irmã ao telefone.
- Yesterday I spoke with my sister on the phone.
- Comeste o bolo todo?
- Did you eat the whole cake?
- No sábado passado, partimos às oito da manhã.
- Last Saturday, we left at eight in the morning.
- Eles beberam um café depois do almoço.
- They drank a coffee after lunch.
The mistake to avoid
In European Portuguese the -ar "we" form needs its accent: falámos means "we spoke", while falamos (no accent) is the present "we speak".
Where this fits in
Falar do passado, Portuguese A2: Contar o que fez ontem, no fim de semana passado, e as suas experiências de vida com o pretérito perfeito.