Unfortunately we do not have any tutorial showing how it can be set, but I would suggest you to create the porous domain (cylinder) to represent the porous media around the tubes, and then set this up in Advanced Concept’s tab. You can also use this project as a guide: Catalytic Converter Flow Simulation with Porous Media by Ali_Arafat | SimScale
But again, I would try it jut with the tube drawing, and then after replicate it using the entire geometry next quarter.
best,