Force Downloads

Im new to lua and i have tried

resource.AddFile(“filepath here”)

which never seems to get any luck. Everytime i restart the server it will not download the materials.

function ForceDownloads()
resource.AddFile(“materials/fw/explode.vmt”)
resource.AddFile(“materials/fw/explode.vtf”)
resource.AddFile(“materials/fw/explode.vtf.ztmp”)
resource.AddFile(“materials/fw/flag.vmt”)
resource.AddFile(“materials/fw/flag.vtf”)
resource.AddFile(“materials/fw/flag.vtf.ztmp”)
end

What am i doing wrong? I saved it as DL.lua and put it in lua/autorun/server