Geometric position in the model of individual elements

Revit
21

It seems that I misunderstood the statement above. Of course it would be better if I could move the Z-axis up and get the respective elements and not have to move the model.

How I apply Level.Elevation I have not yet understood properly (See screenshot). Is there a possibility to “walk” along my Z-axis in small distances and to get the respective elements automatically?
level.elevation

What experiences do you have with the projection on the Z-axis? Since with me also wall materials for Z=0 are issued, which are further not on the Z-axis.

22

I just found a similar topic:

Here the Z-axis has a non-zero value. However, I do not see what is different. Unfortunately, I lack the approach how to get non-zero values for Z.