From a Home screen, navigate: Apps > Settings > Accounts (Personal section).
From the Accounts section (located on the right), tap Add account.
Enter the Gmail address then tap NEXT (located in the lower-right).
Enter the password then tap NEXT.
If presented, configure the following as desired then tap NEXT:
Enabled when a check mark is present.
Back up your device's apps, app data, settings and Wi-Fi passwords
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If presented to Set up payment info, select any of the following then tap CONTINUE (located in the lower-right):
Add credit or debit card
If applicable, complete all remaining steps to set up payment info.