there are two distinct parts to any php/mysql setup.
1st forget html and Dreamweaver.
There are two places you can create a database locally on your own PC and on a web server.
I'm assuming you are running a test server using Wamp or similar?
Open phpmyadmin or one of the other tools and check you have created a database or if not create one. The default super user name is root, the password is I beleive not set.
Once you can connect and log in using root and nothing then you need to run a query.
select open query and then browse to your downloaded files and in the database folder you will see a file users.sql
run that file which will populate your database.
By doing this you have created your table and proved your connection details.
Then in your connections folder edit the lines to show as below
$hostname_localhost = "localhost";
$database_localhost = "your database name";
$username_localhost = "root";
$password_localhost = "";
$localhost = mysql_pconnect($hostname_localhost, $username_localhost, $password_localhost) or trigger_error(mysql_error(),E_USER_ERROR);
Then open users_Registration.php in dreamweaver and preview.
Ok thats the basics but life is never simple. If that does not work come back to us with
your version of Dreamweaver
If you are running on a local machine are you using WAMP or .....
What tool are you using to edit/modify/play with mysql
Are you on PC or MAC
We can then all give you more specific help