Download and install the 7-Zip File Archiver. While other tools like WinRAR may work, 7-Zip is the native utility for .7z formats.
Based on its file extension, is the first part of a multi-volume split archive created using 7-Zip . What This File Is JFV.7z.001
If you get an error saying the archive is "corrupt" or "cannot open," check if a part is missing from the folder. Download and install the 7-Zip File Archiver