The future can be expressed by using aller as an auxiliary verb, particularly for something that will happen in the immediate future. Le Futur Proche ("the near future") can be used to create future statements by combining “I am going to,” “He is going to,” etc. with the infinitive:
I am going…
| Je vais manger un sandwich. | — I am going to eat a sandwich. |
This can be made into a question with est-ce que and a rising intonation:
| Vous allez manger un sandwich? | — Are you going to eat a sandwich? |
A question also is signalled with Est-ce que, or "Is it that…?"
| Est-ce que vous allez manger un sandwich? | — Is it that you are going to eat a sandwich? |
Ask a question by inverting the verb and subject:
| Allez-vous manger un sandwich? | — Going you Are you going to eat a sandwich? |
A question might be preceded with “So…,” which would be alors.
| Alors, vas-tu manger un sandwich? | — So, going you are you going you to eat a sandwich? |
Grammar note: Is it very easy for English speakers to express the idea of doing something in the future as "I am going," which might be expressed as Je suis aller…, which literally translates to English as "I am to go…". However, this would sound like the passé composé construction Je suis allé, which translates as "I am gone" in English but in fact means "I have gone" or "I went" when the passé composé is used to express changes in location or state.
"I am going to Paris" is a common idiom in English, but in fact the English speaker means to say "I am going to go to Paris," or "I am going to Paris soon/next month/someday." Otherwise, if taken literally, the English speaker is saying that s/he is en route to Paris at this very moment: "I am going to Paris (as we speak)."
To make a clear statement of near-future activity in French, the speaker can use le futur proche to say Je vais aller à Paris — "I am going to go to Paris," which translates neatly to English.
A phrase like Nous allon au restaurant employs a conjugated form of aller, but without the associated infinitive, it sounds like an event happening in the moment: "We are going to the restaurant (as we speak)." However, Nous allon aller au restaurant translates as "We are going to go to the restaurant," a statement about the near future.