I use the sanding cylinder for smooths the edges around the top hole to prevent fraying of the cords.
I use the grinder to cut an outline for the pits around the side holes where the cord protrudes, then i put the sanding cylinder back on to sand the pit.
And the engraving/carving tool is used differently for different features, like all the chucks I make since I got the dremmel ive been carving a signature logo, and somtimes I'll write names or words. Here lately ive been trying to get god enough at using the carving tool to cut straight circular lines for grips, but I still need some more practice, or a better technique. all will come with time.