This is just a more detailed version of Karkat Vantus's Setup for the people that need the extra help.

Folder/Files:

• GarrysMod Server (Need SteamCMD to download this)
  
• CounterStrike:Source (You need the "cstrike" folder from within CS:S)
  
• Murder GMA (file found in C:\Program Files\(x86)\Steam\steamapps\common\GarrysMod\garrysmod\addons unless your using a custom location)
  
• GMAD Extractor[treesoft.dk]

These are needed for your server.

First, Lets setup your GarrysMod Server.
Create a Folder on your Desktop and call it "GMOD Server".
Then Download SteamCMD from the linked version above.
Put steamcmd.exe in a Folder and just call the folder "SteamCmd" so you can find it easier.
Double Click the steamcmd.exe in your "C:/SteamCmd/" Folder.
Once Opened and loaded it will need to download files in which that folder comes in handy.
After it finishes the download, type "login anonymous" in steamcmd.exe.
Hopefully it just says "Successfully Logged-In" now here is where we get started.
Type "force_install_dir "C:\GMOD Server" " into the steamcmd.exe.
The text forces the location of where it will install your server.
After that it wont say anything in the console don't worry.
The last thing you need to do is type "app_update 4020 validate".
This downloads your server now we are setup with your GMOD server.
After that you can type "quit" or listen to the CSS steps below

Save SteamCMD you need it for more stuff.

First, Lets setup your CS:S Server.
Create a Folder on your Desktop and call it "CSS Server".
Then Download SteamCMD from the linked version above.
Double Click the steamcmd.exe from your "C:/SteamCmd/" Folder.
Once Opened and loaded it will need to download files in which that folder comes in handy.
After it finishes the download, type "login anonymous" in steamcmd.exe.
Hopefully it just says "Successfully Logged-In" again
Type "force_install_dir "C:\CSS Server" " into the steamcmd.exe.
The last thing you need to do is type "app_update 232330 validate".
This downloads your server now we are setup with your Server.
When done just type "quit" in steamcmd.exe.
Open your "CSS Server" folder and copy the "C:\CSS Server\cstrike" folder.
Paste the folder to your "C:\GMOD Server\" folder.
Now your done with the setup.

When your server is done goto your "C:\GMOD Server" folder and create a start.bat.
If your computer doesn't automatically say want to change your file.
Look up how to enable extensions[windows.microsoft.com].
Then edit your .bat file in NotePad or Notepad++.
Add this to your server.bat:
After that save it and double click the .bat to run the file.
Wait for it to load fully then exit the the two opened cmds that are running your server.

Here is where you can get into editing your server.
Goto your "C:\GMOD Server\garrysmod\cfg\" folder and open server.cfg.
Add the following code to the server.cfg:
After you add that save your server.cfg.
Goto mount.cfg and edit it and change this from:
To this:
Save that file and your done with the editing.

Now that your done with everything else goto your Steam Client and subscribe to Murder.
Go into your game and wait for it to finish the download and then close out of it.
First, download the GMAD Extractor which extracts the .gma which is located above.
Then goto the location above in which Murder.gma is located.
Open GMAD and then click "OPEN" in the top left corner, then click browse after that.
Then goto the location in which your "murder.gma" is located then select open/use.
Then it will send you beck to the browse menu the click on the murder.gma.
Make sure it is highlighted and click slect and then it sends you again to the first menu.
Then click "Extract all" then you select a location just create a folder on your desktop.
Lets call the folder "murder" and then click extract.
Then it will extract a gamemodes folder and a materials folder.
Drag the materials folder into the gamemodes folder then into the murder folder within it.
After that copy the murder folder which you just dragged the materials into.
Paste it to your server but in a new location "C:\GMOD Server\garrysmod\gamemodes\".
Then goto your start.bat and add this after the +maxplayers text:
Then start your server and you should be set.