Guide I wrote regarding this a while ago:
https://steamhost.cn/steamcommunity_com/workshop/filedetails/discussion/261801217/622954302102972129/#c530646080852257507
Also read the rest of the thread if that's not clear. Hope it helps.

One other thing, if you are actually starting the server and it doesn't show up in GMod on the same computer, the dedicated server might not have permission from Windows to access the local network. When you start some programs for the first time, Windows pops up a dialog box asking what network access you want to give it, if you skipped this or denied it access this could break it. If this is the case try these guides:
https://answers.microsoft.com/en-us/windows/forum/windows_vista-windows_programs/how-do-you-give-a-program-internet-access/00f7a19b-3b5e-4d1b-8a09-462f39cc3b68
http://www.pandasecurity.com/homeusers/downloads/docs/product/help/gp/2010/en/34.htm

PixelFelon の投稿を引用：

Guide I wrote regarding this a while ago:
https://steamhost.cn/steamcommunity_com/workshop/filedetails/discussion/261801217/622954302102972129/#c530646080852257507
Also read the rest of the thread if that's not clear. Hope it helps.

One other thing, if you are actually starting the server and it doesn't show up in GMod on the same computer, the dedicated server might not have permission from Windows to access the local network. When you start some programs for the first time, Windows pops up a dialog box asking what network access you want to give it, if you skipped this or denied it access this could break it. If this is the case try these guides:
https://answers.microsoft.com/en-us/windows/forum/windows_vista-windows_programs/how-do-you-give-a-program-internet-access/00f7a19b-3b5e-4d1b-8a09-462f39cc3b68
http://www.pandasecurity.com/homeusers/downloads/docs/product/help/gp/2010/en/34.htm

I sucessfully got the server up and running with no issues and installed turbostroi and the game is running flawless i have even opened up ports for the server so my friends can join and play on the server with me too.