Perfect idea for a "flipped classroom": Send this activity home with your students as homework the night before you want to start working on the passé composé. They'll be ready to start using it the next day, and you can use your precious class time more efficiently.
This lesson is an introduction to the simple past tense (le passé composé). It includes an explanation of when to use the P.C., a review of "avoir" and regular -er, -ir, and -re verbs in the present tense + formation of past participles and how to form the passé composé.
There are links to two of my videos on YouTube (one for the p.c. of regular verbs and one for irregular verbs, but both videos are only for verbs that use "avoir" as helping verb).