Here you are some videos to learn Spanish past tenses: https://www.youtube.com/watch?v=lRThHmUQIaE&list=PLKJikVC-v4E0GkNx_VYLDyHqQEvvoJ4dF

Hi Erika, If you mean that you have a hard time understanding when to use this or that past tense, this may help: • If the action is fully finished, use the pretérito indefinido ("Yo viví con Pablo"); • If the action has just finished, use the pretérito perfecto ("Yo he vivido [recientemente] con Pablo"); • If the action is a narration of a past action, use the pretérito imperfecto ("Cuando vivía con Pablo, …"). Note that the pretérito indefinido (viví) broadly corresponds to the simple past in English, while the pretérito perfecto (he vivido) broadly corresponds to the present perfect in English. Further tip: for the pretérito imperfecto (vivía), this tense is commonly used in secondary clauses introduced by elements such as "cuando", "en el momento", … and can correspond to English simple past, but in the meaning it's closer to the past continuous tense. Hope this helps ;)