Click on the Apple Mail app icon if the app is not already opened.

When Apple Mail launches the first time, the setup menu will open as shown above.

Next, select the "Google" mail account type and click Continue.

Next, enter account details including full name, email address, and password. Click Set Up.

NOTE: If you are using 2-step verification, the password required will not be your normal email or network password, but the one time password generated in the "App Specific password" settings of the 2-step verification process. See the 2-Step Verification and App-specific password setup tutorials for instructions on how to complete this step.

Next, select the Mac apps that will be associated with Google Apps. It is recommended that the apps shown above are selected. Click Done.

After a few minutes, you should begin to see messages show up in the inbox. Click the compose button and send a test email to confirm everything is working correctly.

Next, you will want to setup your email signature in Apple Mail using this tutorial.