It's one room with a sleeping sofa for 2 and a queen-sized bed. We didn't sleep well, either because of a busy day/travel, or because the beds were much harder than we're used to.
While the appartment itself is renovated nicely on the surface, many details are not done well. The environment around the house, and common areas in the house are pretty run-down. Choose another area of Thessaloniki if you care about such things.
The host was communicating very well in English, we felt we got help for any questions we had.