To open a file associated with the Richpeace Garment CAD program, you need to have the software installed on your Windows computer. If the file can only be opened with a teaching app, it may be necessary to have a specific version or module of the software designed for educational purposes. Make sure that your version of Richpeace Garment CAD supports the file type you are trying to open. If you are still having trouble, consider contacting Richpeace support for specific guidance or to inquire about any educational modules or licenses that might be necessary.