We took the metro from the airport which was very straight forward. We did not have rolling luggage so had no issues with the short walk from the metro, as well as two flights up the stairs to the apartment. We met Pedro at the Airbnb - he showed us a few things inside, as well as gave us a fairly elaborate tour of the neighborhood. This was so helpful since we didn't have to go looking for basic things by ourself He showed us directions for the local supermarket, breakfast place, train station to go to Sintra, etc.
Despite being in the heart of the party neighborhood (situated literally across the street from several bars), it was very quiet with the windows closed, especially sleeping inside the room. It may be a bit louder if you are sleeping on the couch but not too bad. The actual area is great for bar hopping and drinking, but as Pedro recommended, many of the restaurants are tourist traps, so it's encouraged to eat at other areas.
The bathroom is quite small with a tiny sink, while the kitchen is large. We did laundry with the washer which was useful, though we needed to air dry the clothes. There were very simple amenities provided such as towels, and ingredients in the kitchen left by other guests. There was no soap, shampoo, or conditioner, but you can easily buy it at the nearby supermarket.
Wifi was fast for basic browsing, a bit slow for streaming/downloading. We used the projector for TV a couple times as well which had many channels.
The apartment kept itself cool on the hotter days, so we didn't need to use A/C.
Overall, we really enjoyed our stay, it's in a good location near all the tourist destinations and the apartment is well kept.