Ensure latest version of Gmail is installed on your device. After that is done, open the application.
Tap the menu icon in the upper left corner > Settings > Add account > Exchange and Office 365.
Enter your full email address and tap Next. Enter your password and tap Next.
Follow any prompts you may get, including security permissions. You may also be asked to set your sync settings and a display name.
Go to your inbox. If you see a message from with a subject that says "Action Required to Sync," follow the below steps. If you don't, skip the below steps and go step 7.
Tap the email message to open it.
Tap the Use another Mail app instead link to enable sync with the Gmail app.
Pull down the Android notification bar by swiping down from the top of your screen.
**If you see a notification that reads "Unable to sync calendar and contacts," tap it. Then tap Allow to give access. NOTE: If you don't see a sync error notification, you're good to go!