You will need a utility like WinRAR , 7-Zip , or The Unarchiver to extract the contents.
Because .rar files are often shared on third-party sites, ensure you downloaded this from a trusted source. Files from unofficial sites can carry malware or unwanted scripts.
The primary advantage of the "GOG" tag is that the game remains yours to keep and play offline indefinitely without digital rights management software interfering.
A file with this naming convention generally contains the following: The main file to run Starsand.