You can add already played game with Game Manager.
- Login and click on "Create game".
- Add all the game details, like date and game formats and continue to second page.
- On "2. Players and Groups" add yourself to one of the groups from the Player Pool (bottom of the page).
- On the 3rd page click on "Add Results for a Played Game" to enter the scores of already played game. You can also add your statistics, click on "Show Stats" on the right side. GIR is calculated automatically.