How do I enable this for my server?

[V-Man]

"switch" refers to "command-line extension," the text in a batch or sh file that is added after telling the file to execute the client binary. For instance,

[SELECT ALL] Code:

ac_server.exe -T

in this example, "-T" is the extension, or switch, which in this case causes the server to put time stamps on all logs.
The main page for the docs can be found here: http://assault.cubers.net/docs/
The documentation for command-line extensions can be found here: http://assault.cubers.net/docs/commandline.html