Right-click mYLllT-SS1St3.7z > Select 7-Zip > Select Extract to "mYLllT-SS1St3.7z/" .
If you found this file in a system directory you didn't create, do not run any .exe or .bat files found inside.
Double-click the file (if Keka/The Unarchiver is set as default) or drag it onto the app icon.