Assuming youre coming outside from eu, after customs turn right on arrival hall, then go down the escalator (the one the leads to malpensa express/sheraton malpensa sign)....walk pass a convenience store....then turn left (exit to malpensa express/sheraton).

Youll pass under a tunnel...after tunnel, turn right...entrance of hotel is there.

Pretty straight forward as there's numerous signs from outside customs until you reach door of hotel. About 5-7 minutes walk starting from arrival hall to hotel.