How do I build the outdoor stairs to the basement?

Hello, I have a cellar door leading outside in my house. I still need to build an outdoor staircase to the cellar here. I thought that a foundation for the cellar stairs could be poured and a prefabricated staircase from the concrete factory could be placed on top. Now, the thing is, below the stairs or the floor slab the house's sewer connection runs. Do I have to take anything into account here, or can I simply pour concrete over it, meaning a blinding layer and then cement on top? There is also a branch off the sewer connection that should then be embedded in the foundation as a drain.

Hello,
You can do it exactly as you describe; the channel connection must not be damaged, so be careful during excavation and concreting work.