Hosting the files is the easy part. Making sure that you don't violate any copyright laws in doing so is the hard part.
To host the files, all you need to do is copy the files into a folder on your web host. Then create a web page with links to those files. If you don't know how to do this, then you should check the resources offered by your web hosting service. They usually include free site builder tools that will help explain how to create a basic web site and link to different pages or files.
As for the copyright, that is a much more complex issue. Just because you own a particular book doesn't mean you have the right to give away copies of it, especially with e-books. You need to check each book carefully and look for the copyright notice to see if it grants you permission to redistribute. Also, if you can't find a copyright notice or a release, you should assume that the book is still protected under copyright. The safest way to ensure that you can do this legally would probably be to contact the author or publisher.