1. Go to the "Dashboard" or home screen of the Xbox Series X/S.
2. Navigate to the "My Games & Apps" section.
3. Select the "Games" tab.
4. Find the game you want to uninstall and highlight it.
5. Press the "Options" button on your controller (the three horizontal lines).
6. Choose "Manage" or "Manage game and add-ons".
7. Select "Uninstall" and confirm the action.

Please note that uninstalling a game will remove all game data and saves from your console. Make sure you are certain that you no longer want to play the game or access the game data before uninstalling it.