The entrance is on the main thoroughfare next to the Qorikancha convent, but the restaurant itself is tucked away on the second floor, through a courtyard, up some stairs, down the balcony. That said, it is well worth wandering around looking for a table. I went twice; once by myself for lunch (the service was rather slow although the restaurant was empty), then with a group a week later for dinner. The staff that evening was ncredibly attentive and prompt. The food was unbelievably good, the presentation worthy of $$$$ restaurants, but without the commensurate cost. The alpaca with quinotto was perfect; on my second visit I tried the pumpkin ravioli - sublime. There's a decent wine selection, mostly consisting of Chilean vintages.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.