There are probably quite a few technical things we need to know as budding web designers. This is just one of them, and applicable only if you host on Apache.

The .htaccess file has a number of important uses. It’s a little off-putting because in most FTP programs you can’t see the file unless you make some changes to the FTP program’s settings. Not being able to pin the file down is not a good start to using it.

But once you have cracked .htaccess’s tendency to invisibility, it is useful in the following areas:

• Specifying your own error pages when, for example someone tries to access a page on your web site that does not exist. If you could design a page that always displays in this case, you could neatly direct them to your home page or your FAQ or whatever you think appropriate. 
• Using .htaccess you can password protect certain directories on your web server. So that forum you just set up, or those files you want to make available for download will only be accessible if the visitor knows the password as well as the URL.
• You can also use .htaccess to prevent people from bandwidth stealing by hotlinking to your images. 

All the techniques you need are explained in the javascriptkit site.