FreeFileSync Forum

Also, downloaded source files to build for this system.
However, there is no information on the build process.

This is a permissions problem. I run Linux and my FFS directory is in /opt.
I give group r/w permissions to users so that GlobalSettings.xml is writeable.
I don't believe the file exists until your run FFS the first time. That is probably why you can't find it....

Try installing it as a user-only ...