Please see Help->Online Documentation->User's Guide and then look in Chapter 5, 'Piping Input' and see the full description of every button (I hope). Another tip for you: Open your input and look at the menu items. The corresponding toolbar button is shown there, giving you a better indication of what the buttons' functions are. Between that and the manual you should be able to understand what all the buttons do. If not, I suggest you experiment on a practice file with all the buttons.