Enabling GameAnalytics in your games is fairly simple. First of all, you need to download GameAnalytics plugin from the Asset Store.

Once plugin is downloaded, just follow 3 simple steps described here:

Active GameAnalytics Support.

Open Unified analytics settings using top menu item.

Windows -> Stan's Assets -> Unified Analytics -> Edits settings

And enable Game Analytics support as shown on a screenshot below.

And you set everything! Feel free to use Unified Analytics API as you normally do, and data will flow to your Game Analytics account as well.

Note:  If you want to use some specific features from a reach GameAnalytics API, feel free to do this. It will not collide with the Unified Analytics. Just make sure you are not reporting the same events with Unified and GameAnalytics since it may cause duplicated records.