I hate it when people tell you to read the manual.
Here's what you need to do:
Open dreamweaver and goto the "Site" Menu, or click on the "Files" Console and then the "Site" dropdown menu.
Choose "New Site"
If you use the Basic tab for Site Definition choose "FTP"
Under host name, ftp.yoursite.com, ie (ftp.howtobeawebmaster.com)
or your ip number if you have one. if your domain name has not resolved or is not pointing to your server then use the ip that your host provider gave you.
Don't put a folder if you want full freedom.
FTP Login is the account username that your host gave you
unless they use an ftp username in which case you want to use that one.
FTP Password is the account password or the ftp password if you were given a differant one for ftp.
usually it's the same username and password as the account.
Click Save so that you don't have to enter the password in everytime you want to log in, unless you're in a work environment where you will need more security.
Then click the Test Connection button. if you did everything right, then the connection will be successful. Common mistakes are mispelling the username, or the hostname. check password as well.
Click next, ignore the Sharing files unless you're going to collaborate with someone.
You'll be presented with a summery of the setup, which you can change later by going to the advanced tab or edit the site definition., so click done, and then click the two connectors on the files console and you should connect.
You'll want to upload any files into the public_html folder if you wish to see them on the net.