Install the SteamCMD from here, This will allow you to install the server from steam, Once downloaded drag the SteamCMD executable into a new folder and run it. Upon running it will proceed with the first time setup and you should see Loading Steam API...ok followed by Steam>
Make a new folder somewhere for your server, the recommendation is making a desktop folder and calling it something simple such as SCP:SL_Server
Head to the SteamCMD and enter the following commands in order
Your server folder should now contain 17 new files and 5 new folders
To start the SCP:SL server open the LocalAdmin.exe file inside of the server files.
Your server is officially created but will need to be somewhat configured in order to accept players, You can go to Server FAQ -> Server Configration to see all config options
Before we get into this, Do Not Install The SCP Server On The Root User!!! Make A SCPSERVER User Or Something Else!!!
First you will need to install mono for the server to work, Go here and read the guide on installing mono.
Then you will need to install SteamCMD, Type the following command sudo apt install steamcmd, That will allow you to connect to Steams servers to install the SCP:SL server.
For some people installing SteamCMD might not work with apt, Such as CentOS, And other Linux distros, If you are one of those people you will need to install curl and use curl to install SteamCMD, Type the following command to install curl, sudo apt install curl
Then you will need to use curl to install SteamCMD, Type the following command, curl -sqL "https://steamcdn-a.akamaihd.net /client/installer/steamcmd_linux.tar.gz" | tar zxvf -
That will create a folder called linux32 and a steamcmd.sh file.
Now that you have SteamCMD install you will need to type steamcmd, If you had the issue as above you will need to type ./steamcmd.
Now that you are inside of SteamCMD you will first need to set the install directory for the SCP Server, Simply type force_install_dir (your server directory) replacing (your server directory) with the folder of where you want the server installed
After setting the install directory you will need to login as a anonymous user to download the server, Simply type login anonymous.
Now you can finally install the SCP Server, Yet again simply type app_update 996560.
Thats it! You have installed the SCP:SL Server! To run the server type ./LocalAdmin followed with the servers port