There a few ways to order a meal at a restaurant in Spanish. I will list them here:

-Me gustaria tomar una ensalada
(I'd like to have salad)
-Tomare ensalada
(I'll have salad)
-Pongame un plato de pescado por favor
(please bring me a plate of fish)
-Tomare la sopa
(I'll have soup)

If you need to take a look at the menu you should say:
Puede traerme el menu por favor?
(could you bring me the menu please?)