When should I use the imperfect to talk about the past in French?

One situation where the imperfect should be used is when giving descriptions of the past - how something or someone used to be. For example, if I wanted to say that the weather was nice yesterday, I would say "Il faisait beau hier". The emphasis is that it was like this for a period of time, rather than just for a moment. For the same reason, the imperfect should be used when talking about repeated actions. If I used to play football a lot, I might say "Je jouais souvent au foot". If I said "J'ai joué au foot", it would sound like I was talking about just one game. The imperfect should also be used when talking about an interrupted action. For example, if I was doing my homework when I got a text message, I could say "Je faisais mes devoirs quand j'ai reçu un texto".