Heres my solution
1. First of all you need to go into the "Accounts and Import" settings of the gmail account that youre trying to add, this is done on your computer.
2. Verify that "Multiple sign-in" is enabled, if not click edit.
3. Enable the account by choosing "on or off", check the boxes that Google requires that you check then click "save".
4. Go back to your phone to add the account(s) add the required usernames and passwords.
5.You should have a list of gmail accounts, they arent in alpha order for some reason.
a) From my limited experience the last account you checked manually is the last viewed. So you can switch between accounts by just clicking on it.
Verify that your account(s) are enabled to sync. (mine were not syncing because of this setting).
1. Click the Gmail icon on your desktop
2. Click the "Menu" button.
3. Click "Accounts"
4. Click "Accounts" again
5. Click "Account Settings"
6. Make sure the Background Data check box is checked and make sure the "Auto-sync" is checked.