The first thing you’ll need to do is jump into the Settings menu. Pull down the notification shade, and hit the cog icon (on stock Android devices, you’ll need to pull the shade a second time before the cog will appear).
From there, scroll down until you see “Accounts.” On some devices, it may be called “Accounts & sync” or something similar.
Depending on how many accounts you’re already signed into on your device, the list that shows up here could be pretty long—just scroll down to the bottom, and there will be an “Add account” link. Tap that.
Again, depending on your exact setup, a lot of apps could show up here (anything that allows you to sign in!), but just look for “Google.” Once you’ve found it, give that little guy a tap-a-roo.
If your device is protected by a PIN, pattern, or password, you’ll have to enter it before you can continue. If the device supports it, you can also use a fingerprint.
On the next screen, just input your Google account info, then password. If the account is set up with two-factor authentication (and it should be!), then you’ll have to wait for the code to come through. Once that happens, you’re ready to go. Just tap “Accept.”
From there, it’ll jump back to the home screen, but if you want to configure synced data (like Gmail, app data, contacts, etc.), you’ll need to jump back into Settings> Accounts>Google, then select the account you just added.
You can now completely configure what sort of information you’d like to sync. For example, I added my work account, where I don’t need things like App Data or Docs, but I do need Gmail and Calendar.