If your just wanting them to download from your server...(Download System isn't very clear).
Just upload the files to your server, put them in a folder for an example say. "downloads"
Then make a page to link to it..Say.. you have 7zip. Make sure the file name matches example "7zip.exe"
Make a link <a href="./downloads/7zip.exe">

ownload 7zip</a>
I'm sorry if that don't help...I don't completely understand what you mean by download system.