you need steamcmd to work
go to this
https://developer.valvesoftware.com/wiki/SteamCMD
If you are in windows
you download a steamcmd.zip
if linux
look at the guides on valve software wiki
After that go to section 2

if you have steamcmd
Go to this page
https://developer.valvesoftware.com/wiki/Dedicated_Servers_List
Then Check if anonymous login is ok if not its not going to work
Like L4D2 is for anonymous thats ok
so all you need to do is this
Change content as any you want
then
type
then Do this
app_update "some appid"
then change some appid without "" quotation marks
like for example
Tf2
232250
and l4d2
222860
once that
Go to section 3

Once that
Type app_update "appid"
same thing as section 2
it goes like this
app_Update 222860
this creates l4d2 dedicated server
then wait
once after that
you will see vpk
now section 4

So after the section 3
all you need
is
gcfscape
and that's pretty much it
so go to the vpk files that starts with _dir
then extract all of the content files
then wait
if done
now cut or copy to your gmod addons
like yourgmodfolder/garrysmod/addons
and put the folder
there
Oh and the maps but that's optional but recommended

there you go done now you import your content game in multiplayer source games
without begging for help for money
done


Ok Cave Johnson Done Here