How to form and use the preterite and imperfect tenses in Spanish (with regular verbs)

"Yesterday I went shopping" is the simple past in English. To express these ideas in Spanish we use the preterite tense. We use it in the following ways:To express a completed action in the past - la semana pasada vi una película con mi mamá.To narrate a sequence of events in the past - Anoche terminé mis tareas y despues me acosté temprano. When talking about actions in the past where the beginning and the end are clearly defined - Mi abuelo vivió entre 1920 y 2012To form it with regular verbs we add the following endings:-AR: é, aste, ó, amos, astais, aron -ER: í, iste, ió, imos, isteis, ieron-IR: í, iste, ió, imos, isteis, ieron"We were shopping all afternoon" In English is the past continuous. To express these ideas in Spanish we use the Imperfect.We use it in the following ways:When an action was in the past but the start and end points are not defined - Vivía en Chile por 8 mesesTo indicate that an action in the past was habitual or repeated - Cuando (yo) era pequeña iba a España cada verano For descriptions rather than events - eras muy cansado en lunesTo say what was happening when a particular event in the preterite occurs - estábamos en colegio cuando lo pasóTo form it with regular verbs we add the following endings:-AR: aba, abas, aba, ábamos, abais, aban-ER: ía, ías, ía, íamos, íais, ían-IR: : ía, ías, ía, íamos, íais, ían