It might be easier if you make changes to a local copy of your website (a bunch of files stored in a folder, presumably) in DW and then upload them to your site manually via FTP.
Your website is just another computer. You need to move files across to the computer hosting your website (a server). With an FTP client, you can have a side-by-side view with local files on one side and files on the server on the other. Try something like Filezilla; it's free, easy, clean, and simple.
Download and install, and enter your FTP login information which your hosting company should have provided you with. Horizontally across the top of Filezilla, there are a few fields. Host is your site's address or IP address, whichever your hosting company needs you to use. Then your username, password, and port (which is 21). Depending on how your hosting is set up, you should see some folders here - you may have to upload your files right in this folder or into one of the folders listed, it depends on your hosting.
Hopefully that helps you understand the process of how this stuff works. I do a lot of web development, just trying to break things down as simple as possible here.
