Assuming you have negotiated the ordering process, a waiter will appear with a bottle of wine and hold it out for you. Don't take it from him. This is merely his way of asking you to check that the label actually shows what you asked for. He will next remove the cork, sniff it and present it to you. You could sniff it as well, but since this is unlikely to tell you anything instructive, I would not recommend it. Far better to just say "thank you." The waiter will pour a sample. Take a deep breath, checking the wine for cork taint. If all is well, taste it to be sure. Nod wisely and say something like "ah yes, the '67. Unmistakeable." When this ritual is completed, he will go ahead and pour the wine.