Imparfait

To build this tense you should drop the -ons ending from the present indicative nous form of the verb and add the imperfect endings:

je -ais nous -ions

tu -ais vous -iez

il -ait ils -aient

Meanings:

I. Habitual actions or states of being

Quand j'étais petit, nous allions à la plage chaque semaine.
When I was young, we used to go to the beach every week.

II. Physical and emotional descriptions: time, weather, age, feelings

Il était midi et il faisait beau.
It was noon and the weather was nice.

III. Actions or states of an unspecified duration

Je faisais la queue parce que j'avais besoin de billets.
I stood in line because I needed tickets.

IV. Background information in conjunction with the passé composé

Il était à la banque quand il l'a trouvé.
He was at the bank when he found it.

V. Wishes or suggestions

Ah ! Si j'étais riche !
Oh, if only I were rich!

Si nous sortions ce soir ?
How about going out tonight?

VI. Conditions in si clauses

S'il voulait venir, il trouverait le moyen.
If he wanted to come, he would find a way.

VII. The expressions être en train de and venir de in the past

J'étais en train de faire la vaisselle.
I was (in the process of) doing the dishes.

Il venait d'arriver.
He had just arrived.

NB! The verb être is an exception for this tense. It's not formed from nous sommes, but takes the irregular stem ét- and the same endings as others.

AND the vous form is étieZ