You can manage your registration on Let's Do This by clicking here, and input your booking reference number in the field. On the next page, click on the "manage" hyperlink that is beside your name associated with your registration.
Then click "edit team selection," and from there you will be able to join a team or create one of your own.
Your booking reference number can be found in the automated registration confirmation email that was sent upon sign-up. If you can't find your confirmation email and/or otherwise need help locating your booking reference number, please contact customer support at info@diplosrunclub.com.