You have two options.
1) take a taxi from the station, it’s a quick ride to the hotel or
2) go on foot. It’s about 12’ walk if you know where you’re going, otherwise it can take awhile as many of the signs are in Japanese making navigation difficult on your first visit with the maps that the hotel provides on their website. I’ve included a better map in this thread.
Getting there on foot:
When arriving at JR Shinjuku station, follow the signs to the East exit. What locals advise: get your priorities straight man, get those upskirt photos whenever possible.
* Btw, it’s prohibited to take pictures within the station.
Once you exit the station, walk straight across the street where you’ll see building with a video billboard. Enter the alley on your left. Follow the directions on the map shown below. The hotel is taller than the surrounding businesses nearby so you’ll be able to notice the hotel sign placed towards the roof.
