"Shall" is a modal auxiliary (helping verb). In German, I think the equivalent would be "Was werden wir bestellen?" "Was wollen wir bestellen" would be like "what do we want to order?" and "was sollen wir bestellen" would be like "what should we order?" The colloquial usages might be a little different, but in any case, German does have an equivalent construction for such things.
"Bestellen" alone just translates to "order" or "are ordering." This is just the beginning of the different voices, tenses and moods of verbs!
Good question although I am sure you have moved past it. Still I thought it worth pursuing.
"Stellen" is the root word. It means to put or place "be-" Inseparable verbal prefix that signifies: 1..working on something or change of state, 2..touching the object, OR 3...mentioning or discussing the object. "bestellen" 1..To order, demand delivery, summon 2..To convey (a message, e.g. greetings) 3..To cultivate, till
"Mentioning or discussing" what you would like to "place"= "to order"
bestellen ~ order, booking ~ buchen 'Bestellen' is used when you 'order' something like a meal, things from a catalogue or an online shop or even a car etc. I think I'm right in saying things that get brought or sent to you. You use 'booking' for things you reserve/pay for. Things like a holiday or a hotel, tickets for a concert - things that you go somewhere to to use and in German that's 'buchen'.