HSE Guesthouse, Vavilova, 7
The HSE Guesthouse is located within a walking distance from the metro station "Leninskiy prospect" ("Ленинский проспект"), orange line, South. First one should take an unnamed street and then Vavilova street (Вавилова), see the map. Directions, pictures and other useful information is available here. One should show documents at the reception and then take the elevator. A person at the reception will help. To get to the Steklov Institute you can walk 20 minutes straight along Vavilova street away from the center of the city or you can take the trams 14 and 39 from the station "Metro Leninskiy prospect (Yuzhnii Vyhod)" ("Метро Ленинский проспект (южный выход)"), which is just in front of the HSE building, to the station "Ulitsa Gubkina" ("Улица Губкина"), 4 stops along Vavilova street.
Getting to the Guesthouse from the airport
There are three international airports in Moscow: Sheremet'yevo (KLM, Air France, Aeroflot), Domodedovo (British Airways, Iberia, Lufthansa) and Vnukovo (Air Berlin, Germanwings). All three are connected to Moscow through a railway, called Aeroexpress, with moderately priced tickets (500 rubles, approx. $7).
The Aeroexpress timetables are available from their official site. The point of arrival is a rail terminal, which is connected to a subway station: Byelorusskaya for Sheremet'yevo, Paveletskaya or Verkhnie Kotly for Domodedovo, and Kievskaya for Vnukovo.
The best way to get to the HSE Guesthouse from Domodedovo airport is to take Aeroexpress and change it to Moscow Central Circle at “Verhniye Kotly” station (the first stop from the airport). You can take a train towards Krymskaya there and the second stop, Ploschad Gagarina, is your destination.
At night (between 1am and 5am) the most convenient option is taxi, but during the day it can be very slow due to traffic jams. A taxi at the airport desk should cost 1500-2000 rubles (20-30$), if you have a smart-phone there are online-services (Uber, Yandex.Taxi, Gett) that start from 850 rubles (13$).
The map of Moscow Metro (subway) is found in Wikipedia. You should go to the orange (Kaluzhsko-Rizhskaya) line, if you go from the green line, you change at Tretyakovskaya-Novokuznetskaya, if you go by the brown line, you change at Oktyabr'skaya. The price of a subway ticket is fixed and does not depend on duration and range of the trip.
Yandex.metro may be helpful for Moscow subway navigation.
You can buy a local SIM-card in the airports,
prepaid SIM with 3GB of mobile traffic start from 390 rubles
($6)
http://russia-travel-guide.com/tips/how-to-buy-local-sim.php