Press the SLICER mode button to set the PADs to SLICER mode.
The 8 pads represent 8 sequential "Slices" in the Beat Grid. The currently playing Slice is represented by the currently green lit pad. The light will move through the pads as it progresses through each 8-Slice phrase. Press a pad to repeat that Slice (hold it down if you want to keep looping it).
Once the Pad is released the track will continue to play from the position it would have been if the pad was never pressed.
Hold SHIFT down and then use the Pads to repeat the memorized Slices (the Slices played/repeated last time)
Use the PARAMETER buttons to adjust the length of the Loop applied to the slice. Hold SHIFT down and then use the PARAMETER buttons to adjust the step (size) of the Slices
Read further details about Pads in the VirtualDJ 8 manual Sampler