This is gonna be a challenge because the method of accessing the necessary apache file totally depends on what operating system and access you have to the said system. Can you give us more details like:
do you have SSH access? Is this hosted at a company like godaddy?
If you have access to a control panel from your service provider, try looking for something like "Apache Configuration" or something with the logo of a multi colored feather.
If you have access to the server via SSH, you can edit it using a terminal based text editor-- but only do that if you feel comfortable.
Also, .htaccess may not work. Most apache installations will not allow you to over-ride the configuration with an .htaccess file without explicitly allowing it (this is called the Allow Override option).
Best of luck!