Question

can someone explain the preterite uses to me?

Answer 1

This link can explain the preterite use in Spanish.
http://www.studyspanish.com/verbs/lessons/pretreg.htm

Answer 2

The perfect preterite is used for actions in the past that are seen as completed. Use of the perfect preterite tense implies that the past action had a definite beginning and definite end.

Juan habló de la una hasta las dos.
Juan spoke from one until two o'clock.
(clearly stated beginning and end)

It is important to realize that the beginning and the end may not always be clearly stated.

Juan habló dos horas.
Juan spoke for two hours.
(implied beginning and end)

Juan habló con la estudiante.
Juan spoke with the student.
(implied beginning and end)

The imperfect preterite is used for actions in the past that are not seen as completed. Use of the imperfect tense implies that the past action did not have a definite beginning or a definite end.

Las chicas hablaban en inglés.

The girls used to speak in English.
(no definite beginning or end)

The basic difference between the perfect preterite and the imperfect preterite:

The perfect tells us specifically when an action took place.
The imperfect tells us in general when an action took place.