And here is my reply:
Use the shortcut from Prop & Trees Anarchy mod (default is shift + p, but it can be used by other mod, so change it in that case).
Then the props are easy to snap on top of anything (not on the walls, but on the roofs etc.).

Do you know how to use it now

Unfortunately no idea. I still did not find time to make cleanup in my mods and assets or even try vanilla game with some newer DLCs (not really tried Industries). So I have only started a game a year ago to try new computer:-).

If you want i can write a little instruction, so first you need to turn the mod on in the content manager then mods and then this mod, how you use it it helps snap props on buildings or on the side of building if you want to move it you can use move it and it still snaps on the building it's a very helpfull mod :-)

hallo ich habe diese mod installiert aber ich kann nicht auf das dach oder auf wand das schild setzten warum nicht