How do I form the passé composé?

In French, the perfect tense (or passé composé) is formed using the present tense of the verb avoir (for all verbs except for a few exceptions which use the present tense of the verb être) and what we call the past participle of the verb you want to use to describe the activity that someone did. To form the past participle of regular verbs, we remove the -er, -ir  or -re ending and add: -é for -er verbs, -i for -ir verbs and -u for -re verbs. There are some irregularities, but this rule works for most verbs. So, for example, you might want to say "Yesterday, I played tennis." We know that in the present tense, to play tennis is jouer au tennis. We would take the present tense 1st person singular (I) form of avoir, which is j'ai and then to form the past participle of jouer we take off the -er ending and add -é to make joué. The whole sentence would read 'hier, j'ai joué au tennis.'