Welcome to Android Central! Add Account is there if you want to add an additional account. Are you sure Google Play Music isn't already logged in with your account? On the main Play Music screen, swipe in from the left--do you see your Gmail address at the top of that bar?
If not, then tap Settings>Google account, and then tap the Gmail address that is listed there (DON'T tap Add Account). Now see if it asks you to sign in. If it asks you about All Access, just tap Use Standard.
04-14-2015 07:21 PM