When a slider is finished you can select it and then hold Ctrl and leftclick in order to add additional slider anchors to manipulate the shape.
If you do that on an already existent anchor it will become red and cause the slider to make a sharp turn on it.
To make an actual repeat, hover over the slider in the top timeline and you will see your cursor turning into a drag icon:
Hold down your left mouse key and drag it to the right to create as many repeats as you want to. In order to remove repeats, drag into the other direction.