You're in the IDK forum, but unfortunately the IDK is... dead.
https://blog.roku.com/developer/idk-deprecated
But! You didn't actually need the IDK. You needed Direct Publisher.
However. Direct Publisher is... also... dead.
https://blog.roku.com/developer/rdp-sunset
My advice would be to wait for the dust to clear, and in a few months have a look around and see what new 3rd-party solutions have sprung up to replace Direct Publisher.
If you decide to build your own with the SDK, do look through the certification requirements before you commit to that, to give you an idea what you need to deal with above and beyond your own functional requirements.