Your website host should have an FAQ or Help section, with server-specific details.
You'll be wanting to look up "FTP".
If you are using software such as Dreamweaver or FrontPage to make your site, you can set those programmes to auto-upload whatever to your website... but you'll still need the FTP details from your website host.
If the server help pages don't cover what you need, I can post a pictorial on setting up the FTP prog called "WS-FTP".
(I'm assuming you have webspace)