1. 1.
    Download the latest version here
  2. 2.
    Decompress the zip.
  3. 3.
    Navigate to the AppData\Roaming Folder: %appdata%.
  4. 4.
    Place the Synapse Folder from the Zip at the Root of your AppData Folder.
  5. 5.
    Open your Server Files and navigate to {ServerFolder}\SCPSL_Data\Managed and place the Assembly-CSharp.dll from the zip in it.
  6. 6.
    Start the Server and have fun!
NOTE: The Synapse Folder you placed in %appdata% contains all configs and Plugins