By car :
Highway Zürich-Chur until Thusis, then Julierpass until Silvaplana, then left to St. Moritz.

By train :
Train until St-Moritz, then a taxi until the Youth hostel.

By air :
The two closest airports are Zürich and Milan (both about 2.5 hours by train from Zürich airport, for example).

Parking :
Possible parking spot around the Youth hostel (not included in the package)