Without more specifics, I’ll just say it’s as easy as letting them download from any html page. All you need to do is add the link to wherever you uploaded the file. There are lots of ways to go at it, including just sticking links on a template, having all the links on a single ‘static’ display weblog entry, or entering a new article for each download/group of downloads. Of course, if it’s in EE, it makes it easier to restrict display access to members only. Note- this only restricts display, if someone knows the direct link to the file, they could still download it.
Hope that helps a bit!