copy pasta from the first post:
GUIDE TO THE BEST WAY TO PURCHASE GAMEPASS
BEFORE YOU START. If you are already subscribed to Game Pass, let it lapse before following these steps. They will work for new or lapsed accounts, but not for active ones.
1. Buy 3x 12-month Live Gold codes (£40 each) from CDKeys or equivalent. It might take an hour or so for the codes to come through, but they will eventually.
2. If you don't have one, create an Xbox account on the Microsoft site.
3. Redeem your Live Gold codes on the MS Site - clic