First, type in the tag that centers the characters, which is [ C E N T E R ], just without the spaces. Then, after you've typed in the [ C E N T E R ] tag, type in the color tag. Also, by the way, you don't have to type in the color tag, you can click the icon above the Quick Reply box that has A v in it, then select the color you'd like to use. Which is, in this case, blue. There are several different shades of blue in the color selector, so use whichever blue you like best.
I hope this helped. If you have any problems, just send me a PM. ^_^