Flipper v10 is preset to only work a TV - this means the Channel buttons are mapped to the TV.
So if you have a TV Only setup, just sync the code for your brand, and then test all the functions.
If you have a TV and STB / Cable box, then you need to sync the STB to map the Channel buttons to the STB. Look for the code in the list for your manufacturer / brand, then: press and hold STB till solid, then enter the code. Then test Channel.