This new breed of single-button / LED channel-selecting vtx is great. Not sure why it took so long for the industry to get away from DIP switches, but I welcome the change.
Basically, you long-press the button to change "bands" and short-press the button to change channels. There is a row of 4 LEDs that indicate which band you are on, and a row of 8 LEDs to indicate band.
Band F is ImmersionRC / FatShark