the use of the word 'devoir'

Bonjour Bobbie

"We were supposed to ------" is translated as "nous devions", the imparfait, an incomplete historical situation.

Expressing continuing action with the imperfect tense in French (L'Imparfait)

Hope this helps

Bonne continuation

Jim 

Bobbie, 

take a look at the link below which supplements Jim’s answer. 

As usual, there are other ways to express the idea, if that’s what you are asking ?

 Using "devoir" in the imperfect tense versus the compound past in French (L'Imparfait vs Le Passé Composé)