How to Make an .htaccess File

The .htaccess file goes into the root directory of the server hosting space, where the homepage is, and should look just like that - .htaccess - with no file extension after.

You can create the file on your hard drive, in a text editor like Notepad (which will automatically append .txt to the filename), upload it using your favorite FTP program, and change the filename to .htaccess

Another way is to create the file right in the hosting control panel. It's the easiest way, and it's the way I do it because the simplest way is always better as far as I'm concerned.

You may possibly be better off doing it through the control panel, since if the server for some reason does not support it, or if you make some dastardly typo, the site may not function, and return a server error - a 501. It makes it very easy to just nuke the file and make the corrrection if you're already logged in to the control panel.

Redirection Using Mod_Rewrite | Redirecting the Homepage
Redirecting Web Pages using mod_alias | Creating an .htaccess file
File Sizes | Web Safe Colors