If I have some files I want to copy from my project into the .\\bin\\debug\\ folder on compilation, then it seems I have to put them into the root of the projec
.\\bin\\debug\\
Personally I prefer this way.
Modify the .csproj to add
.csproj
PreserveNewest %(Filename)%(Extension)
or generalizing, if you want to copy all subfolders and files, you could do:
PreserveNewest %(RecursiveDIr)\%(Filename)%(Extension)