On the corner Ligovskiy pr. and Kuznechniy per. there is a sign Stolovaya na Ligovke, cafe, you walk on Kuznechniy per. and pass by this sign, after this cafe there is our arch with closed gates (the arch is between that cafe and the red sign 'MTC'),
the code on this gates is '2007B' on the left wall near the gates, then gates will open, go inside and after the arch turn to the left and you will see the entrance where you should dial '4B' (the sign 'Station Hostel' is on the door).