Create hexa mesh from block divided geometry

I have always used salome for non structured meshing, and want to explore the strucutured side, from my little understanding, for these we should

  1. divide our geometry in 6 faced blocks
  2. create a compound of the geometry
  3. mesh it using 3D: hexahedron (i,j,k), 2D: quad mapping, 1D: wire discretization/number of segments_1
  4. if we need different number of cells in one direction, we add the submesh with another 1D discretization and use wire discretization/number of segments_2 and change the desired number

nevertheless, I have several question that would like if someone could enlighten them.

  1. is there any tutorials about this type of meshing? outside of the O-grid that is in this forum
  2. I have created a geometry in another CAD software that uses the parasolid kernel, and divided it in blocks inside of it. my issue is that one of the side looks like it is divided in 2 different surfaces and then the algo fails. i have tried to ‘delete’ this extra wire without any luck. how someone would approach to solve this issue to be able to create the complete geometry in a structured hexa mesh?

here is the .step file
Part Studio 1.step (43,1 KB)
the troublesome block is when the compound is exploded, the part 7