The C4DtoA installer puts the C4DtoA plugin in the default location: the plugins folder of the Cinema 4D install.
If you want to put C4DtoA somewhere else, like a shared network location, you can use the C4D_PLUGINS_DIR environment variable to point to your custom plugin location.
For example, on Windows I moved C4DtoA to a different drive and then set my environment like this:
set C4D_PLUGINS_DIR=F:\plugins set PATH=F:/plugins/C4DtoA/arnold/bin;%PATH%
Note that I had to set PATH so C4D could find ai.dll, and that I had to use forward slashes (on Windows, C4D doesn’t like backslashes in the PATH and drops them).
On Windows, the C4DtoA installer puts a second copy of ai.dll in the C:\Program Files\MAXON\CINEMA 4D R17, so you’ll have to remove that ai.dll, and use PATH to point to the ai.dll in the C4DtoA arnold/bin folder.