< Can you please give a detailed step-by-step

Seems yet written ;)

If you want absolutly a square grid of holes or any special gride
- draw a vertical line at the center (or any place following your wishes) to a top
- Draw your grid of lines from ground to top
- Draw a vertical cylinder at the center
- Transform / Orient / Line-Line none Copy enable
so copy your original cylinder along the lines on quarter or half quarter of the grid (very easy ! )
- then some Mirrors Symmetry
- Return all and draw your spheric object
and Boolean Diff as above
and use the Beamfarmer or other method for the vertical cylinder side
All that take 1 minute :)