You would import the file and folder generated by PowerPoint into your
existing website files and folders, establish navigation link(s) from your
existing pages to the presentation.htm file, and then upload to your
website. The "how" really depends on what you use to maintain your site. I
use FrontPage and I publish to my website from within FrontPage. Others use
external FTP capabilities. Still others use Dreamweaver, etc., etc.