SELES and LSEditor do not, and cannot, connect to the internet, and so are inherently fully safe to use.
Installation is very simple - just unzip and run.
Requirements: Windows 10 or later (64-bit).
(a) Unzip the download file (SELES.zip) in a convenient location. Includes required DLLs and user documentation.
(b) To run SELES.exe or LSEditor.exe, simply double click on the file name (recommendation: make a shortcut on your desktop to the executables).
