Very nice!
If you've got your ACU licence and you've joined the DSC, you'll need to make sure you've signed up for the DD series - email
desmodue@ducatisportingclub.com and they will sort you out. You will be given a race number for you to use.
Once you've done that, you'll also need to join New Era MCC, as they run the DD series on behalf of the DSC. Contact details are on their website at
http://www.neweramcc.org/ and they will send you their membership pack with your New Era card and a load of forms for each race round. Just fill in the forms (you put in your ACU and New Era numbers, along with your racing number) and send it all off. You usually get the entry tickets and cards the week before the race round.
Then it's a case of turning up, getting through scrutineering and not falling off
Good luck!