An XML file is an Extensible Markup Language file. It is a windows file type that can contain data or text in a very specific format. If you double click on an XML file is should open it in IExplorer and you can view it. Yes you can drag and drop or cut and paste it into your Mach directory, BUT, it will overwrite the existing file that is there. You might want to rename the old XML file first to .old or .bak or .jnk or something you can remember before you copy the file over.
As for the motor noises, sounds like they need to be tuned. The other XML file might take care of your problem. I am not much of an expert on the motor part yet though. You might want to go into the config->motor tuning and change the settings.