My advise to you is if you dont know where to put styles you really aught to lean some basic HTML instead of relying on a WYSIWYG editor to do everything for you.
You need to add the bit I gave you to the head of your document.
That is the bit between the head tags near the top of your code.
You will also have to put the style tags around this if you have no other style in your code.
Here is an example on where it goes.
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">