Thanks a lot to both Petr and Karolina. They replied messages quickly and always willing to help. They offered clearly sightseeing information of Prague by email and some guidebooks and maps in the apartment. Also, It was really great experience to stay in such a comfortable and well equipped apartment. We had big dinning room, great kitchen, laundry room, 2 toilets and 4 double big beds. In Addition, We could reach metro and tram station easily by feet. And there are pub, supermarket, bakery, fast food shops and cafes around in walking distance. It's really a good place to accommodate such a big group like us, no one needs to sleep in sofa bed :D Highly recommend this tidy place to everyone who wants to visit Prague.