Wide v2.stp (8.5 MB)
So this looks like a clean STP file, not the ones imported with millions of triangles converted from STL files. I am not able to remove edges, mark and move, just nothing.
Any idea why and what I can do to work on this model?
What edges you want to “move”? It looks ok, don’t see any problems.
I am trying to lower the faceplate as far as possible. Did you load it and move faces/parts? For me nothing works. No move, no deletion of faces, cant change anything literally.
I’m not sure I understand what that means. 
It looks like you’re trying to perform invalid operations. S3D is a CAD tool for working with solids, and there are certain operations you can do. What you’re describing sounds more like surface modeling rather than solid modeling.
Not trying to work surfaces but move parts which is solid. But OK Shapr cant work it it seems.
Parts are moving easily.
But I assume you trying to do something else and calling it “move”.
Can you make a video showing what exactly you trying to do?