Data Conversion Tool, Possibly XSLT

I periodically have XML data files that are generated for each event we photograph. These file have a dedicated extension but are actually just XML files. I don't need all of the data just some of it. Also 7-12 of the data nodes are stored as attributes ie, <data> value="value" name="firstname" </data>. This data would also need to be transformed and exported along with the rest of the data I need. -Data The Data fields would consist of: FileName AdjustedFileName LastName FirstName Grade Position StudentID Password Custom1 Custom2 Custom3 Custom4 (Some of these fields including the custom fields may or may not be present) Multiple instances (Subjects) would typically range from 25 - 1800 instances in a file. -Options I would like the option prior to export to insert a (PC) fixed absolute path for both image fields. If possible, an option for multi level sort ie, by grade, then teacher, then last name. -Output XLSX preferable, but could possibly utilize CSV or TXT. -Thoughts The data I'm looking for is nestled among 50 or more total data points and is tied together in a 'relationship' section that connects some of the data through a "subjectDataId" and an "imageId" that points to the image data. I am assuming that the solution I required is most likely an XSLT file but I am aware that I know just enough about this to really screw it up on my own and am open to possible solutions. I have attached a smaller sample data file.