The official Microsoft documentation is here.
**** NOTE: If you have been using Outlook with Zimbra, you must follow a specific set of steps before configuring Outlook for Office 365. The instructions can be found here.
1. Open the Control Panel Mail Tool. Click the Windows Menu button, type Mail in the search bar and click Mail.
2. If there is still a profile from Zimbra, remove it. Click Add to create a new profile.
3. Type the name of the new profile and click OK
4. Select E-mail Account and enter Your Name and E-mail Address if they are not already filled in correctly. Click Next
5. Enter your email@example.com as the username and your GT password
6. Outlook should find the correct server information. Check Change Account Settings and click Next.
7. Uncheck Use Cached Exchange Mode. Click Next.
**** NOTE: Using Cached Exchange Mode allows for a fuller 'offline' experience, but can lead to throttling or slow sending rates. There is no real ability to check to see if you have been throttled so unless you really need the offline data, disabling Cached Exchange Mode is recommended.
8. Click OK to close the Mail Tool window