Other Two Point Hospital Guides:
Missing Your Golden Toilet? Read Here!
You need to head here twopointhospital.com, where you should be prompted to redeem the golden toilet through Steam.
Once that’s done you’ll need to log into your Steam account, authorise SEGA to activate keys. As long as you own the game you should then be greeted by a ‘DLC Redemption’ success message. Then the DLC should appear in your steam account.