There are generally two ways to activate buttons choose menu options on the display: through the use of dedicated hard keys and joysticks around the display or by directly selecting options on the screen using a touch screen display.
A touch screen display is often easier to work with because it provides a larger array of context-sensitive dedicated buttons that perform specific functions and graphical icons. A touch screen display is more often found on higher-end infrared cameras.
Some infrared cameras us traditional hardware buttons to activate menus and select menu options. Higher end models use touch screen displays.