Simply connect the hard drive to the laptop. The laptop should recognize the external hard drive in a few seconds and assign it a drive letter. Example would be as a D: Drive or E: Drive assuming those letters are currently being use by another drive. Then simply install the game to the external hard drive. When you want to play games simply attach the hard drive to your Acer laptop/tablet combo (which I assume is running Windows).
Caveats....
- If the external drive appears as the F: Drive when you install games, then anytime you want to play that game or install another game, then you need to make sure that it appears as the F: Drive in order to launch the game.
- You can only play the game on the laptop / PC on which you installed...