how to set documentroot in httpd.conf?

[ydok]

>hello,sir; >        i install apache on linux,and i changed >documentroot in httpd.conf ,it looks like this: >DocumentRoot "/opt/apache". >i create the file index.htm in /opt/apache,then >i restart apache and visit <http://localhost/index.htm>http://localhost/index.htm through browser. >but,the page was not found. >why?