You can check out our video tutorial here.
You can make your selection by clicking and dragging across the waveform. You will see alternating dark and light blocks. These blocks represent the beats of the music which have been automatically calculated. In the top right of your selection, you can see the total number of beats you have selected.
To turn your selection into a loop, simply click on the loop button in the playback control section and then press play. (If you do not see alternating blocks when you make your selection, it is because you are zoomed too far out. Try zooming in a little. This will give you more accuracy when making your selections)
It is not currently possible to adjust the start and end point of your selection but we will be making this possible in future versions of Riffstation.