This site explains how to validate your iController export. It offers you different ways to easily do validation, but they are all based on the same xml-schema. You can download the schema and an example export as reference. You should have already received a personalized description of the required structure of the export. We do have a detailed reference of the complete export structure but, be aware, because not all fields are required to be exported for your iController, you should primarily rely on your personalized documentation.
This way of validation lets you do everything offline and is recommended for large exports because the online validation has upload limitations and can be slow for large files.
Online validation is the easiest option but it can become tedious because always uploading the file can be slow. This is why option 1 is the preferred method.
If the export file is too large to upload, you can always upload a zip archive (.zip or .gz, no .rar allowed) containing the export file. All xml files contained in the archive will be automatically validated.