How to ride the elevator:
The big star next to the “1” button in the elevator identifies that as the ground floor / main lobby of the building and thus floors 2, 3, 4, etc. are above floor 1, and the upper floors of a building are never labeled with letters – letters are reserved for the parking levels. Which means that if you drove into the underground parking lot, you will not find your car on the second floor of the building when you come back from lunch, no matter how many margaritas you had.
(I understand that some buildings give the parking garage levels numbers, but if the elevator offers both letters and numbers, it’s a pretty safe bet your car is not on 3 and is instead on C.)
Edited to add: when I came back from lunch, there was a couple of tourists riding the elevator up and down (they didn’t know which floor to choose) and they finally asked me how they could get across the street to a popular tourist attraction… I was hard pressed to hold in the sarcasm, but I directed them to the ground floor (via the helpfully-starred “1” button) and around the corner of the building.