Step 1: Open System Preferences
Enter System Preferences and click the Keyboard icon. All of your existing combinations for OS X can be seen and edited under the Keyboard Shortcuts tab.
Step 2: Select an application
Select Application Shortcuts and click the plus symbol that appears. Decide whether you want the new shortcut to affect all apps, or just one in particular.
Step 3: Enter a process
Enter the exact name of the menu command you want to use. If you’re unsure, open the app and use the menubar to double-check.
Step 4: Choose a shortcut
Enter the combination of keys you want to use and click Add. You can delete any keyboard shortcut you no longer need using the minus symbol.