1) Purchase the demo version of Alan Wake II using the link: xbox.com/en-us/games/store/alan-wake-2/9pnzh065x7pv
2) After the purchase, go to the page of the first part and claim it at no additional cost: xbox.com/en-us/games/store/alan-wake-remastered/9nkb1b50pzlz
3) Enjoy playing for free.