It is about 10 km from Belarus Station, the Moscow terminus for trains to/from Belarus (Minsk and Brest), Kaliningrad, Smolensk and international destinations including Vilnius, Warsaw, and Berlin, to the Oksana Hotel.
By taxi
Depending on the time of day, the journey by taxi will take about 30 minutes, but should not cost more than $25. If you prefer, you can pre-order a transfer with a driver to meet your train here.
By metro
From Belorusskaya Metro Station, take the brown circle line two stops clockwise to Prospekt Mira, change to the orange line and continue north three stops to VDNKh Metro Station. The Oksana Hotel is around 300m from the metro.