You can see what is currently setup in the sites-enabled directory (etc/apache2/sites-enabled IIRC) then create a new site in the sites-available dir (/etc/apache2/sites-available IIRC) - I'd recommend copying one that's there already and use that as a template. Then enable your site (there's a command you'll find if you google, although AFAIK simply creating a symlink will have the same effect).
All this can be done with Webmin too, which is probably easier if you're not familiar with Apache
You need to add an additional site
You can see what is currently setup in the sites-enabled directory (etc/apache2/sites-enabled IIRC) then create a new site in the sites-available dir (/etc/apache2/sites-available IIRC) - I'd recommend copying one that's there already and use that as a template. Then enable your site (there's a command you'll find if you google, although AFAIK simply creating a symlink will have the same effect).
All this can be done with Webmin too, which is probably easier if you're not familiar with Apache