UNIX for Dummies Questions & Answers

I am trying to learn how to install HORDE for work and I found this link:

Installing Horde on Centos 5.x - William Lindley - wlindley.com

I am at this step now:

You'll need to use the MySQL root password. Then, in your database administration screen for MySQL, set the password for the new MySQL user “horde” to something nicely random and hard to guess; keep a momentary record as you'll need it below.
--------
How do I get the database administration screen for MYSQL?

have you got MySQL installed at your system? If yes, is there a user named horde? If yes, you need to change password for that user to something hard to guess and remember it.

I see the user horde but when I try and reset the password it says the user does not exists!!!