When Done, you’ll be taken to the next section where you can separately enable or disable syncing of your Gmail messages, Contacts, Calendars and Notes.
Enable Google Contacts by flipping the Contacts switch (see the top right screenshot), which will turn it green, and you’re done.
You'll see a list of your apps — not alphabetized like the data-usage display, but in descending order of their battery usage.
The announcement was part of Google’s phasing out of Microsoft’s Exchange Active Sync protocol in favor of Card DAV and Cal DAV, which represent HTTP-based Web DAV client/server protocols for contact and calendar items, respectively.
You are then prompted to enter your Apple ID password to complete the installation.
If you know your password, just enter it to unlock your i Device–that’s it.
To Restart or Reboot your i Pad air, i Phone or i Pad touch; Looking Button.
Now look for the DNS and input 18.104.22.168 (is a Google Public DNS– which will ensure safety and speed) and make sure your i OS 10.3.1 device has enough space to download.