Sebastião picked us up at the airport and answered our questions. He told us the most important spots to visit and the best things to try (pastel de nata...). The apartment is provided with everything you need for a pleasant stay (Wifi, coffee maker, towels,...are available). It is clean and cosy, but small (sufficient space for 2). The shower is a little narrow.
You can have breakfast / aperitif in the small courtyard which is sheltered from the wind. For the usual provisions, there are a few corner shops around. The tram 28 stops around the corner and the next Metro station is not far. You can also reach many important sights by foot.
Elsa and Rui mailed us some helpful suggestions for sightseeing, restaurants, etc. which was perfect (no tourist traps!). The travel router is really useful (if you don't lose it en route...).
Altogether we had a wonderful week in Lisboa!