Bit of a back breaker but doable.

Standard way - You'll need an appliance dolly (dolly with a strap), and some friends. The legs come off the game and it should have a strap around it or plastic wrap to keep the head folded on the cabinet, and the it gets strapped in the appliance dolly.
One person above lifting one step at a time and 1 person at the bottom pushing. If you have a friend or 2 for help just cause it's a lot of stairs that would help.
If you don;t want to buy a dolly you can rent one from a uhaul type store.

Easy way - Find someone with a escalara, which is a dolly that climbs stairs by itself.

Naw, I've never taken the head off a modern machine for moving.

The first layer of stairs wont be terrible becasue you'll be fresh. So you'll be taking a little rest at the 1st landing

But then only 6 stairs after that...not bad.

You may be able to get the game still in the box all the way up the stairs. Looks like you'll need to unbox it before going inside (note: not sure if you mean a NIB madness).

There are places that rent escalaras. I would look into that as a possibility.

Appliance dolly, another guy, time, and a 6 pack.

Just make sure to have a socket wrench with a 5/8 attachment. I’d recommend having someone to help you out the legs back on although I’ve done it myself. Just lift up and put a chair under the machine and then rinse and repeat.

This video is from GAP. Pretty good video that shows you how to set it up.