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Well, what game?
In general: Double click on the .dmg and drag the app to your applications folder.
 
Step 1: Buy game.
Step 2: Open game manual.
Step 3: Turn to page that says something like "Installation", usually in big letters.
Step 4: Follow instructions on that page.

--Eric
 
it is rome total war

In that case, add these steps:

Step -2: Buy Windows.
Step -1: Install Windows on MacBook using BootCamp.
Step 0: Boot into Windows.

Now proceed to Step 1 from my previous message.

--Eric
 
Make sure when you buy a game for your mac that i was MADE FOR A MAC
 
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