When do you use the preterite tense?

The preterite tense is used to talk about completed actions in the past, actions that have a defined beginning and end. It's often accompanied by phrases that give a specific time frame. e.g. - la semana pasada fuimos al cine; e.g. - ayer ví a mi madre en el supermercado.

It's not used to describe people, events or situations in the past.