What is the issue you are having?
Walls will automatically trim with other walls based on the building material strengths.
Strong materials cut weaker ones.
There are ways to stop that from happening, but let's not worry about that yet.
Let's find out what your problem is.
One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10