Inputs

BSDF 1
BSDF 2

Here you can link both BSDF layers you want to layer. BSDF layers can, for example, be output by the Uber Surface node.

Blend Factor [0..100%]

This setting can be used to blend the result of layering BSDF 1 and BSDF 2. If set to 0%, the result of the shading description of BSDF 1 will be ouput; if set to 100%, the shading description of BSDF 2 will be output. In-between values will produce a corresponding mix of BSDF 1 and BSDF 2 as a result.