First of all you have to load the mod_ssl module. Many distributions and packages have this module shipped by default, otherwise check the documentation of Apache how to do this.
To configure a default SSL/TLS aware virtual server, you should add at least the following lines to your httpd.conf or ssl.conf file:
LoadModule ssl_module modules/mod_ssl.so
Listen 443
<VirtualHost _default_:443>
DocumentRoot /home/httpd/private
ErrorLog /usr/local/apache/logs/error_log
TransferLog /usr/local/apache/logs/access_log
SSLEngine on
SSLProtocol all -SSLv2
SSLCipherSuite ALL:!ADH:!EXPORT:!SSLv2:RC4+RSA:+HIGH:+MEDIUM