The front panel is the user interface of a VI. Generally, you design the front panel first and then design the block diagram to perform tasks on the inputs and outputs you create on the front panel.
You build the front panel using controls and indicators, which are the interactive input and output terminals of the VI, respectively. Controls are knobs, push buttons, dials, and other input mechanisms. Indicators are graphs, LEDs, and other output displays. Controls simulate instrument input mechanisms and supply data to the block diagram of the VI. Indicators simulate instrument output mechanisms and display data the block diagram acquires or generates.
Select View»Controls Palette to display the Controls palette and then select controls and indicators from the Controls palette and place them on the front panel.