I think you misread a bit and they worded it very poorly.
Brewing Righteous Leicht Bier requires blending two different beers. A German style Pilsener with an OG of 1.048 and a BU of about 35 should be brewed the week before, fermented and lagered at 35F. A portion of this lagered Pilsener will be blended with the brewed, fermented and lagered Leichtess Bier.
So the recipe is for the Leicht Bier but you have to also brew a pils to blend it with.