Our experience with Cataldo and the appartment was amazing! He ans his girlfriend were very nice to us and made us feel welcome right away. The appartment was really clean and we got our own bedroom. The bathroom and living room are shared. Towels and bath/shower things are provided. The appartment lies just outside the city centre. If the weather allows, I would recommand to walk into the city centre. Within 15-20 minutes you will walk up to Royal Mile, after passing the Palace of Holyroodhouse (summerpalace of British Royal familiy) and Holyrood Park. Also, you will pass an amazing fudge shop on your way up the Royal Mile. If it is raining or cold (which it can be in Scotland, haha!) you can take bus 35 into the city centre (about 15-20 minutes) or you can take a cab (around 7 pounds). If you walk from the appartment to the main street, there are a lot of bakerys and supermarkets where you can get your breakfast or a snack. Also, if you do not want to go out for dinner, you can get some food and use the kitchen in the appartment.
About Edinburgh itself: I would really recommand booking a free tour (yes you need to book it online though it will cost you nothing),
Also, I would recommand booking a Ghost Tour as well.
There are a lot of amazing second hand bookshops and you can enjoy yourself with nice pubs with live music every night.
I would definitely recommand Edinburgh to visit and while you are staying here, I would recommand staying at Cataldo's place.