Learn Turkish: Restoranda garsona sipariş verdik. - We gave the waiter our order at the restaurant.

You would add the question particle mi at the very end. The verb verdik already includes the past tense marker and the personal ending for "we", so the question particle just follows it as a separate word: Restoranda garsona sipariş verdik mi?

Why do restoran and garson have different endings (-da and -a)?

The ending -da on restoranda means "at" or "in" (the locative case), showing where the action happened. The ending -a on garsona means "to" (the dative case), showing who received the action. You gave the order "to" the waiter "at" the restaurant.

Why isn't there a word for "our" attached to sipariş if the translation says "our order"?

In Turkish, sipariş vermek is a common phrase that literally means "to give order" (to place an order). Turkish usually drops possessive words like "our" when the context makes it obvious whose order it is. The "we" ending on the verb is enough clue.

Should sipariş have the specific object ending (the accusative case) since it is the thing being given?