Are you hosting your server via your computer? Or is it dedicated? If it's dedicated you should be able to login to your host on the website, for example mine when logged in looks like this:
http://gyazo.com/7282fd2624fd058245586a65b4fb0399 This way, everything that goes in the File Manager, gets sent to the server after syncing it.
If you're hosting it, it's different. You're going to need to setup fastdl manually which also isn't that hard.
Go into your server files and open server.cfg. In there somewhere put:
sv_downloadurl "
http://www.YourFastDLLinkGoesHere.com/username/foldername/"
The link is where the files will be sent to the server from. For this part, If possible I'd buy a dedicated website, they're very cheap and it makes it way easier as you can put the fastdl directory on it. (You basically create a directory on the website with a folder where all your files you want on fastdl go). After this, add these into the server.cfg too.
sv_allowupload 1
sv_allowdownload 1
So, It would look like this:
sv_downloadurl "
http://www.YourFastDLLinkGoesHere.com/username/foldername/"
sv_allowupload 1
sv_allowdownload 1
that should work, I think... for Lua's too, everything in there should be sent to the server for people to download when they join...
