Get mesh structure information from Visualization Library

I’m using that library Visualization Library: Visualization Library Reference Documentation ; Visualization Library: OpenGL vs VL Feature Mapping
I’m a huge beginner but I need to get the data of the mesh hold by a vl::Geometry instance . the structure I need is very simple , a classic one : an array of the vertices ( float3/double3 not per face, just per vertex ) array of face vertex count(per face) and an array of indices referenced by the vertices of each faces…

so for a Cube it looks like this :

 1. [0,1,2,3,4,5,6,7](float/double 3's)
 2. [4, 4, 4, 4, 4, 4](int)
 3. [0, 1, 3, 2, 2, 3, 5, 4, 4, 5, 7, 6, 6, 7, 1, 0, 1, 7, 5, 3, 6, 0, 2, 4](int)