Detailed
Settings
Section

Optic STB GT-V Ultimo 4K 5G OTT Box with Android 11 and Bluetooth RCU and Air Mouse

You can turn Groups / Categories ON and OFF, Rearrange them with Long Pressing OK Button to Hold and Release a Category / Group, Add New Categories / Groups (and assign channels to them) from Settings Section
Choose whatever Background Image and Flag you like from hundreds of available Images and Flags or upload your own using your Smartphone by scanning a QR code
You can do a lot of Customizations and set Defaults from Interface Section of Settings Page
In Information Section of Settings Page, there are Video Tutorials available for your help