You can create a catalog from a catalog template and the exported excel file.
After you complete the Excel worksheet to specify component size detail in Excel, you can build or add to a PCAT catalog file. You can also create a Content Pack.
When you build a catalog from an Excel XLS file, the XLS file is first audited to determine if a Catalog can be created. The audit will also warn you if any data is missing.
After the audit, you can save to a PCAT file or create a content pack. A CTPL catalog template file is not required to build a catalog.