What a lovely little BnB. It is a beautiful place and easily accessible to the Barberini metro station, and a few blocks away from the Trevi fountain and Spanish steps. It is right on the corner of Via XX Settembre and Via Quattro Fontane.
Mrs. Anna, the caretaker, was a fabulous lady. She didn't speak much English, nor I or my friend any Italian, but we managed. Never underestimate the power of sign language! Down to the details:
a. The intercom you need to press is 9A - Trevi. This confused us initially at first as we were looking for the number 4 for fourth floor :)
b. You will get three sets of keys: one for the main door, one for the door to the apartment, and one for your room. The key for the main door goes into a key hole ON the intercom, not the door itself.
c. There is a lift in the middle of the staircase. Use it ;) It's tiny but safe. Don't forget to shut the doors to make the lift move.
d. The water pressure for hot water could be better, but it wasn't just "little more than a trickle." Also, depending on the time of day, it could take some time to get the water hot.
e. They easily accommodated our need for an extra bed, which was right beside the main one. The main bed was a little too firm for my taste, but my friend found the small bed comfortable.
f. Towels, shampoo, and a hair dryer are provided. You should make your bed yourself.
g. Breakfasts were comprised of pastries, juice, and coffee.
h. There is a friendly neighbourhood kitty. Adds lots of character to the place!
i. There are lots of plugs to charge your devices with. I left my adaptor there, so hopefully you'll get some use out of it ;) (UK to EUR)
j. There is NO wifi in the place. The closest free wifi hotspot we've found is a cafe across the pharmacy on the corner of via delle Quattro Fontane and Via del Tritone.

All in all a very beautiful, clean, and well maintained building/bnb. I would stay here again, but would ask the host to consider installing some wifi! Thanks to Mrs. Anna and Emanuele!