This isn't the easiest mod to install, given that you must do a template edit.
Do you have any budget for this? You can ask for paid help over
here.
Thing is, you've already failed step 1. Nobody told you to upload the file via FTP. You were supposed to download the file, unzip it, and carefully read all the instructions. Only
after understanding the instructions were you supposed to do anything else.
.xml files are imported via your AdminCP>Plugins and Products>Manage Products. Template edits are done in AdminCP>Styles and Templates>Style Manager