Instructions
Insert "The Sims 3: Ambitions" expansion pack CD and click "install" from the menu that appears. Select the install directory and enter the CD key that appears in the game booklet. Accept the user license agreement, click "Next" and wait for the expansion to install completely.
Open "The Sims 3" launcher and click "Play."
Wait for the introduction video to finish and for the game to load to the main menu.
Click "New Game" in the bottom-right corner of the main menu. Click the arrow in the box under "Select a Town" and choose Twinbrook (third option), then click the round check mark button at the bottom of the screen.
Wait for Twinbrook to load; it can take five to 10 minutes, and may appear to be frozen.