If you already have a Games With Friends account and you have NOT yet set a password you will need to set one:

Tap here to set a password.

Alternatively, if you have the original device your account was created on you may use the following instructions:

1. Open the game on the device you used to create the account (iPhone, iPod Touch, iPad or Android).
2. Tap on the "Account Settings" button.
3. Set your new password.
4. Tap "Save and Close."
5. Open the game on your new device and login with your newly set password.