Learn Portuguese (Portugal): Não devemos beber café à noite.

In Portuguese, the ending of the verb tells us who is doing the action. The verb devemos already means 'we should', so adding the pronoun nós (we) is optional and usually left out.

Why is the second verb beber left in its dictionary form?

When you have two verbs working together to express one idea, only the first one (devemos) changes to match the person. The second verb (beber) stays in its infinitive or 'to do' form.

What does the backwards accent on à in à noite mean?

That accent shows that two words have merged. It combines the preposition a (at or to) with the feminine article a (the). Together they make à. So à noite literally means 'at the night'.

Can I put não after the verb, since we say 'should not' in English?

No, in Portuguese, the negative word não always goes immediately before the verb it is negating. You must say não devemos, never devemos não.