The exact panel displayed is dependent of the context:
If you are printing from the SD card or through USB (i.e. from Cura, OctoPrint, …), the Print panel is displayed.
This panel has the following tools on the top:
A Back button to exit this panel. This does not stop or suspend the current print
A Stop button to abort a print. A panel is displayed asking you to confirm this action and then the print is stopped when the current move is finished.
A Pause button to suspend the current print. The head will move on the back of the printer (parking). When it is done, the printer beeps. To resume the print, tap on the Continue button (top-right corner).
A Change Filament button. The head will move on the back of the printer (parking) and the current filament is unloaded. When it is done, the printer beeps. Insert the new filament and tap on the Continue button (top-right corner). The new filament is loaded and when it is done, the print will resume.
A Baby steps button that displays a new panel and allows you to adjust slightly the position of the head on the z axis to get a perfect first layer.
A Print Options button to displays a new panel and allows you to adjust print parameters like the temperature of the head or of the bed, the speed of the fan, etc.
If you are not printing and a SD card is inserted in the SD slot (and readable), the SD Card panel is displayed. Otherwise, the Temperature Graph is displayed.