Hi Daniel, and welcome to both Dozens and to this community
That’s not a dumb question at all.
Dozens is still relatively new and we have not yet launched the facility to set up Direct Debits and Standing Orders. These will be available in the near future (still a couple of months probably) as we are in the process of a major upgrade and change to our systems.
We announced last year that we had made a few changes to our architecture, and will be switching to using Visa. We also have some other partners we will be integrating with at the same time, so lots of changes will happen at once that will give you a lot more options, including also Apple / Google Pay, IBAN numbers and more.
Until then we are not part of CASS.
You can open and use your Dozens account in the interim, and if we don’t yet have all the services you need, you can use the other features without needing to move all your financial dealings to this account. We do not charge fees for the account, and there are no “minimum requirements” for balances for example, so you can get to know the app better while we launch the full service.
I trust your 
arrives soon 