I receive regularly the question how to find the activation code when it is not given with the geocoin. For all trackables that can be tracked at geocaching.com you can find the activation code as follows:
Activation is always done through this page: https://www.geocaching.com/track/activate.aspx
If you have your activation code, easy, just enter it in the section indicated with the blue arrow and follow the instructions.
If you don’t have your activation code, easy too, click the link indicated with the red arrow and follow the instructions. Once you have the activation code, return to the page and enter it in the section indicated with the blue arrow.