Dynamically placing a mesh onto another custom mesh

I have created a custom mesh from via the from_pydata() function.
The mesh functions as a floor and looks like this:

All the vertices of the floor are at the edges of the floor.

I now want to move an object on top the floor by changing it’s coordinates and rotation and then calling the render-function.
However I don’t know how to place my dynamic object on top of the floor.
My problem would be solved by retrieving the position and rotation of a specific “face-pixel” at a certain position.

I would be glad if someone could help me out.
Thank you!