No apps panel on my TV

My TV is UN55KU6300FXKR. But I can find APPS panel to enable developer mode.

How can I enable the developer mode?

You are showing the apps panel in your image. Use your remote to enter the number to enable developer mode. You may have to be signed into your Samsung Account I don’t remember if I did that before or after entering developer Mode

Ron
Samsung DeveloperProgram