If you wish to register as a coach, you must first have an account at the The International 29er Class Association events site. If you don't have an account here, you'll need to create one.
Once you have logged in with your account, you'll see the Coach Registration link on the home page beneath the 2022 European Championship event:
Once you've completed the coach registration form you'll be returned to the home page. You'll now see a section at the top asking you to complete the checkout process by paying for the registration.