When you have questions regarding modifications, you need to post them in the modification thread - the thread where you downloaded the file.
Regarding the xml files.... they are usually products which you do not upload via ftp, but instead go to Products & Plugins > Manage Products > Upload Product. Manual pages -
Plugin System
Templates are in Styles & Templates > Style Manager > find your style in the list > Edit Templates. You may have to expand the templates to see them all... click on the <<>> button to expand them all. Double-click to edit. Manual pages -
Styles & Templates
Advise.... always read a modification thread prior to installing a modification. That way you may see what sort of issues people are having before you install the mod. Also, if you have a test site, always install the modification first on the test site to make sure it works for you.
I hope that helps.