When do I use the imperfect tense?

It can seem confusing but the for the imperfect it is important to remember:-it describes something from the past-it is used to talk about things that used to happen - habits from the pastFor example: "I used to walk to school everyday." - Tous les jours, je marchais au college.Notice it is different to: "I walked to school yesterday." - Hier, j'ai marché au college.