Where can I find "platforms" with training material for the design of Smart TV APP?

Question

User interface

Hello
I set out to study design for applications for applications for smart tv. Actually, a question. Could someone tell me where to find "platforms" with applications / competitions / training material on this topic. The official GUIs are also interesting. I am a mobile app designer. I decided to explore this area further. I will be grateful for any info. Thank you.