How does one distinguish between the perfect tense (passé composé) and the imperfect tense (imparfait)?

The perfect tense (passé composé) is used to depict a single past action that has been completed. Specific time phrases such as 'last weekend' (le weekend dernier), 'last week' (la semaine dernière) and 'last month' (le mois dernier) allow us to recognise that the action has happened once, therefore the perfect tense is needed. Example: Last week I went to the cinema - La semaine dernière je suis allé(e) au cinéma. On the other hand, the imperfect tense (imparfait) is used to depict series of ongoing actions that have occurred in the past and are now completed. This tense can be seen alongside more general time phrases such as 'when I was younger' (quand j'étais plus jeune) and 'when I was in school' (quand j'étais à l'école) because it is uncertain when the action started and ended. Example: When I was younger, I used to go to the cinema - Quand j'étais plus jeune, j'allais au cinéma.