The Channel Shortcut keys are performing the normal functionality as Red, Green, Yellow and Blue keys but can also be reprogrammed to select your favorite channels.
The different Icons on these keys are used to divide them into genres, so that you are able to organize your Channel Shortcuts.
The App Shortcut keys are used to open apps on your Smart device such as Netflix, Amazon Prime Video or YouTube. If your original remote control has a button for Streaming services such as Netflix, the App Shortcut keys will perform the same function. If you were able to watch streaming services, but had no button for it, you can use the App Shortcut keys to program a macro on it.