Do not worry about the table name. vBulletin will automatically create them for you when you do the installation.
In your configuration file (config.php), do not worry about the tbl_prefix, you can leave that blank
unless you have other tables in that database.
Since you just created the database, I assume that you are safe with leaving it blank.
Now that you have created the database, go ahead and try and connect with your vbulletin installation script and let us know what happens.
