In French, there are two important ways to talk about actions in the past: passé composé and imparfait. They each have their own rules and uses.

Passé Composé is for actions that happened and are finished. You form it by using special helper verbs "avoir" or "être" along with the main verb that you change a bit (this is called the past participle). Here are some examples:

• "J'ai mangé" means "I ate."
• "Elle est allée" means "She went."

Imparfait, on the other hand, is used for actions that were ongoing or to set the scene. To create this form, you take the "nous" form of the present tense, remove the "-ons," and then add different endings: -ais, -ait, -ions, -iez, -aient. Here are a couple of examples:

• "Je mangeais" means "I was eating."
• "Elle allait" means "She was going."

To sum it up:

• Use passé composé for actions that are completed.
• Use imparfait for actions that happened regularly or to describe background details.