Right-click only the first file ( SDF part 1.rar or SDF.part1.rar ) and choose "Extract Here." The software will automatically pull data from all parts to reconstruct the original file. If you can tell me: Where you found or downloaded this file?
To extract the content, you usually need all the parts (part 1, part 2, part 3, etc.) to be in the same folder. SDF part 3.rar
Use software like WinRAR (Windows), 7-Zip (Windows), or The Unarchiver (macOS). Right-click only the first file ( SDF part 1
This is a part of a multi-volume RAR archive, which is a common format for compressing files. software) you expect it to be?
What (game, document, software) you expect it to be?