When you add ply lining and some vinyl to your van floor you will find that the original VW side door step doesn't fit too well and the vertical wall at the back of the step is not tall enough to fit over the top of your floor.
You have the choice to either - accept a gap under the step and try to fill it with a piece of timber, or replace the step with this version that VW produce for Kombi vans. The Kombi step is 9mm taller than the standard van step and works very well with 12mm ply flooring covered in vinyl placed directly on the metal van floor.
The step has a hole in the right hand side for a light fitting (light, plug and cable available) or you could blank it with a piece of plastic or wood glued on the reverse side. The step is suitable for vans either with a sliding door on the left (UK) or the right (EU).