If this is your first time running Smasher, you could try the presets before working on new loops of your own.
If you press the light play button ( ) on the transport toolbar you will hear the original loop, whereas the darkened play button ( ) triggers playback of the sliced version with effects.
Try selecting random cells in the topmost grid (labelled 'pattern') and then press the dark play icon once more. You will notice that the order in which slices are played has changed. Consecutive slices are arranged left to right, so if you draw a diagonal line from SW to NE, the slices will be played in reverse order.
Next try selecting a few cells in the row labelled 'reverse' in the grid below. You could also experiment with a few of the other effects, but it's fair to say that not all effects suit the default drum loop.
To change the loop without having to load one of your own, select the 'Presets' tab in the Controls book on the left. Each preset consists of a sample and a machine state. To get to know the effects better, listen to and edit the various presets.
When you close the application, the current machine state is saved.