We loved the apartment, which is small but has everything you need. On the first floor so not too many steps to climb! The kitchen is well equipped with utensils for cooking etc., plus a toaster, microwave, hob, kettle, and coffee machine. The apartment was clean and modern. The bedroom has hangers, a mirror, a few drawers for clothes. The bathroom is quite small but was fine for us - it might be a bit of a squeeze for some! The main door feels nice and secure.
The apartment is right in the centre of the old town and is near a couple of bars, but the windows are really good at keeping the sound out. We had one night when our neighbours were a bit noisy, but otherwise it was quiet.
The apartment is close to lots of restaurants and is nice for wandering round soaking in the atmosphere. (We really liked the restaurant Tasca do Jaime close by for Fado music and lovely food). There are also small shops close by for souvenirs and grocery shopping. The metro stop Terreiro do Paço is about a 10 minute walk away. We found ubers were a good method of getting around but you may not get right to the door due to the narrow streets; we called the uber from the main street a couple of minutes walk away.
Overall I would recommend the apartment if you want to stay in the old town. Lisbon is a wonderful city, enjoy!